Cable racks for reduced stress and increased load capacity

ABSTRACT

Methods and devices for reducing stress and for increasing the load-hearing capacity of cable racks supporting electrical power and communication conduits and cables having increased versatility for conduit and cable sizes and quantities. Underground devices including rack arms for these applications are desirably made from plastic or composite materials. Rack arms desirably include openings for tying down the conduits and cables atop the arms. While non-metallic materials are designed to withstand environmental stresses, they typically have strength and rigidity properties less than the metallic structures previously used in such applications. Non-metallic rack arms with such openings may be reinforced locally with a stress attenuator or with ribs to increase their load-bearing and buckling capacity and to reduce their stress, strain and deflection under load. A stress attenuator may be made by increasing the in-molded thickness of the web in areas adjacent to or surrounding the tie-down openings.

CLAIM TO PRIORITY

The present application claims the benefit of U.S. Provisional Appl.63/149,709, filed Feb. 16, 2021, which is hereby incorporated bydisclosure.

FIELD OF THE DISCLOSURE

The technical field of the disclosure is that of racks for supportingpower and communication cables in underground manholes, vaults, andtunnels.

BACKGROUND

Cables for electric power and for communication lines are rununderground in order to protect them from above-ground elements and fromthe interference and damage they would suffer when installed above theground or on poles or structures. The underground environment may beless hostile in some ways, but the history of underground cablessuggests that the underground environment is not to be consideredbenign.

Cables for electric power, control and communication lines are rununderground in order to protect them from above-ground elements and fromthe interference and damage they would suffer when installed above theground or on poles or structures. The underground environment may beless hostile in some ways, but the history of underground cablessuggests that the underground environment is not benign. The environmentin underground power and communications manholes is indeed harsh.

Cable racks or supports are used to organize and support medium voltagepower distribution cables in underground manholes, vaults, and tunnels.Cable supports are also used to organize and support underground lowvoltage power cables and control cables, high voltage power transmissioncables, and communication cables. Cable supports may also be used aboveground and in areas other than underground manholes, vaults and tunnels.

While there may be fewer ultraviolet rays and less severe weatherunderground, and the temperature is more constant, moisture and humidityare always present. There are other considerations, such as the constantand higher danger from flooding, and underground pests that considerelectrical insulation, and even steel, a tasty treat. Manholes may fillwith water that is often contaminated with sewage, fertilizer runoff,tree roots, and chemicals, including caustic materials. Very harsh seaor salt water sometimes fills manholes. Many manholes are completely orpartially filled with such contaminated water all of the time, exceptwhen pumped out for maintenance. Others fill periodically but are hotand have extremely high humidity, while still others fill and empty withocean tides.

As noted, most power and communications manholes are partially orcompletely full of water some of the time or all of the time. The amountof water in a given manhole is influenced by location, surroundingconditions, drainage, and weather. Manholes located at higher gradesgenerally will be filled with less water for a shorter period of timethan those located at lower grades. Manholes located where thesurrounding area has a high ground water level and/or a high amount ofrain generally are filled with water to a higher level and more of thetime than those located in areas that have a low surrounding groundwater level and/or a low amount of rain. The water level in manholeslocated close to the ocean often changes with the tide, and theconstantly-changing interface only increases the likelihood forcorrosion. Water in underground power and communications manholesoccasionally is fresh and clean but most often is contaminated, as notedabove, or is salt water. Both of these can be very corrosive and alsoconductive.

Communication and power cables should be kept off surfaces such asfloors or the ground and should be organized and protected to thegreatest extent possible. Cables are thus typically supportedunderground by racks that elevate cabling and keep the cabling off theground, thus shielding the cables from at least some of the worstunderground dangers. Racks for supporting cables must be able towithstand both heat and cold, in all conceivable temperatures andhumidities in every combination. In addition, the racks must be able tosupport very heavy loads from power and communication cables and havethe versatility to vary the cables sizes and quantity. The racksthemselves are preferably supported, e.g., attached to a wall, ratherthan free-standing structures. Thus, the racks will have penetrations,or stress concentrators, to deal with, in these hot, humid, andstressful environments, along with the high loads expected fromsupporting cabling. The walls themselves may have penetrations forsupporting bolts, pins or other fasteners used to secure the racks inplace. The walls, such as concrete walls or other structures, will alsobe in intimate contact with the racks, adding their chemical potentialfor corrosion to the racks.

All these stresses combine to make the underground a challengingenvironment for cable racks. For the most part, existing cable supportsused in underground manholes, vaults, and tunnels are manufactured usingsteel stampings, steel forms, or steel weldments. They may also beductile iron castings. After the supports are stamped, formed, welded,or cast, they are hot dip galvanized in an effort to prevent corrosivedeterioration. The steel arms and posts are bonded together and groundedin an attempt to prevent corrosion. Eventually, the galvanized coatingis consumed and the steel racks may oxidize or corrode away, leaving thepower and communications cables without support.

Two phenomena, galvanic corrosion and stray current corrosion, occur inflooded underground manholes to cause this deterioration. Galvanizedsteel cable supports are very vulnerable to both galvanic and straycurrent corrosion and often become severely corroded to a point thatthey will no longer support the cables in a very short period of time.

Galvanic corrosion is an electrochemical process in which one metal, theanode, corrodes preferentially when in electrical contact with adifferent type of metal, the cathode, and both metals are immersed in anelectrolyte. In flooded underground power and communications manholesthe galvanized steel cable supports are the anodic sites of the galvaniccorrosion reaction. Cathodic parts in the manhole, parts made from morenoble metals such as stainless steel, may be damaged in the galvaniccorrosion process due to generation of electrolytic hydrogen on theirsurfaces causing hydrogen embrittlement. Stray current corrosion ofunderground power and communication cable supports is usually caused bypower and communications manholes being located in the vicinity ofelectric rail tracks, pipe lines that are cathodicly protected or thelike.

Underground galvanized steel cable supports that are severely corrodedand can no longer support the cables result in power and communicationsinterruptions and a safety hazard to technicians who enter the manhole.Another safety issue is that galvanized steel cable supports areconductive. If a power cable's insulation is compromised and theelectrified conductor contacts a galvanized steel cable support, thecable support is energized. If a technician inadvertently touches theenergized cable support he may be electrocuted.

All these stresses combine to make the underground a challengingenvironment for cable racks. In the past and still today, manyunderground cable racks and fasteners are made from hot dippedgalvanized steel. Underground cable racks, with cable rack arms andsupporting stanchions, made from non-metallic plastic or compositematerials, resistant to corrosion are now available. Spacers made fromplastic or composite materials are also available. While products madefrom plastics or composites are much more resistant to the environmentand the stresses discussed above, the materials from which they are madeare not as strong and stiff as the steel or other metals currently used.What is needed are cable racks, cable rack arms, stanchions and spacersthat are better able to withstand the stresses and strains of theirenvironment and have the versatility to vary the cables sizes andquantity. These more versatile products should better withstand theloads imposed on them with lower stresses, less deflection and load, andfor longer service.

BRIEF SUMMARY

One aspect of the disclosure is a non-metallic cable rack arm. Thenon-metallic cable rack arm, includes an upper portion formed between aproximal end and a distal end of the cable rack arm, a lower portionopposite the upper portion and a web having a nominal thicknessconnecting the upper portion to the lower portion, the web comprising atleast one orifice for securing a load atop the non-metallic cable rackarm, wherein at least a portion of the web adjacent the at least oneorifice comprises a thickness greater than the nominal thickness of theweb. The increased thickness of the web acts as a stress attenuator forthe cable rack arm.

Another aspect of the present disclosure is a non-metallic cable rackarm. The non-metallic cable rack arm includes an upper flanged portionformed between a proximal end and a distal end of the cable rack arm andalso having a lower flanged portion opposite the upper portion. The rackarm also includes a web having a nominal thickness connecting the upperflanged portion to the lower flanged portion, the web comprising atleast one orifice for securing a load to the non-metallic cable rackarm, at least a portion of the web adjacent the at least one orificefurther comprising a thickness greater than the nominal thickness of theweb, and an interface near the proximal end for securing the cable rackarm to a mounting stanchion. In one aspect, the portion of the webadjacent the at least one orifice may have a thickness at least twicethe nominal thickness of the web.

Another aspect of the disclosure is a cable rack arm. The cable rack armincludes an upper portion formed between a proximal end and a distal endof the cable rack arm, the upper portion adapted for holding at leastone cable and also includes a flanged lower portion opposite the upperportion, the flanged lower portion formed at an acute angle to the upperportion. The cable rack arms also includes a web having a nominalthickness connecting the upper portion to the lower portion, the webhaving at least one orifice for tying down the at least one cable and aninterface near the proximal end, the interface comprising horizontalorifices and a vertical slot contiguous with the horizontal orifices,the vertical slot further also comprising side reliefs adjoining theproximal end of the cable rack arm, the interface suitable for mountingthe cable rack arm on a flanged stanchion, wherein at least a portion ofthe web adjacent the at least one orifice further comprises a thicknessgreater than the nominal thickness of the web.

Another aspect of the disclosure is a non-metallic cable rack arm. Thenon-metallic cable rack arm includes a major cathetus upper portionformed between a proximal end and a distal end of the non-metallic cablerack arm, the upper portion adapted for holding at least one cable and aminor cathetus side portion formed at about a right angle to the majorcathetus upper portion. The non-metallic cable rack arm also include aweb having a nominal thickness connecting the major cathetus upperportion to the minor cathetus side portion, the web comprising at leastone orifice for securing the at least one cable to the major cathetusupper portion, at least a portion of the web adjacent the at least oneorifice further comprising a thickness greater than the nominalthickness of the web, and an interface near the proximal end. Thethickness greater than the nominal thickness of the web is effective forat least one of: reducing stress on a point of the non-metallic cablerack arm by at least 15% for a given load; and increasing a bearing loadcapacity of the non-metallic cable rack arm by at least 25% for a givenmaximum stress of the non-metallic cable rack arm. In other embodiments,the thicker portions may be effective for reducing stress a minimum of25% or increasing load-bearing capacity of the non-metallic cable rackarm a minimum of 35 percent for a given load.

In general, at least one of these, reducing stress or increasingload-bearing capacity by at least 15%, can be achieved by an increase inthe thickness of the web. As seen and described in the examples herein,at least such a 25% increase can be achieved by making the web thicker,as described herein. This may be accomplished, as described herein, bymaking portions of the web, as described herein, at least fifteenpercent thicker, twenty-five percent thicker, thirty-five percentthicker or fifty percent thicker. This is what is meant by a thicknessgreater than the nominal thickness of the web, to improve rack armperformance.

Another aspect of the present disclosure is a method for supportingpower and communication cables. Steps of the method include furnishing anonmetallic cable rack arm, the nonmetallic cable arm comprising anupper flange, a lower flange and a web of nominal thickness extendingbetween the upper flange and the lower flange, wherein the web furthercomprising two orifices for securing the power and communications cablesto the nonmetallic cable arm, and wherein at least a portion of the webadjacent the orifices further comprises a thickness greater than thenominal thickness of the web. The steps also include mounting thenonmetallic cable arm to a stanchion and placing at least one power orcommunication cable atop the cable rack arm. In one aspect of thedisclosure, the cable rack arm is secured to the nonmetallic stanchionwith at least one fastener, wherein the at least one fastener comprisesa material selected from the group consisting of nonmetallic,nonmetallic composite and metallic materials.

Another aspect of the present disclosure is a non-metallic cable rackarm. The non-metallic cable rack arm includes a proximal end, a distalend, and also includes a top formed between the proximal end and thedistal end of the cable rack arm, the top including at least one orificefor securing a load atop the non-metallic cable rack arm. The cable rackarm also includes left and right sidewalls connected to the top and tothe proximal and distal ends of the cable rack arm. The top of the cablerack arm may be flat, except for the at least one orifice, or there maybe two or more orifices in the top.

Another aspect of the present disclosure is a non-metallic cable rackarm. The non-metallic cable rack arm may include a top portion formedbetween a proximal end and a distal end of the cable rack arm, the topportion comprising a plurality of orifices. The non-metallic cable rackarm may also include a back portion adapted for mounting to a stanchion,left and right sidewalls connecting the top portion to the back portion,and a reinforcement under at least one of the plurality of orifices.

There are many other aspects of the disclosure, of which only a few aredescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of stanchions with rack arms in anunderground installation with embodiments of the present disclosure;

FIG. 2 is a closer perspective view of one of the stanchions of FIG. 1 ,showing rack arms of the installation;

FIG. 3 is a rear perspective view of a rack arm;

FIG. 3A is a partial view of a bracket from the rack arm of FIG. 3 ;

FIG. 4 is a front perspective view of a stanchion according toembodiments of the present disclosure;

FIG. 4A is a rear perspective view of the stanchion of FIG. 4 ;

FIG. 4B is a close-up view of a holding aperture of the stanchion ofFIG. 4 ;

FIG. 5 is a perspective view of a locking barb useful in embodiments ofthe present disclosure;

FIG. 6 depicts a side cross-sectional view of the installation of FIG. 1;

FIG. 6A depicts a close-up elevational view of the upper arm of FIG. 6 ;

FIG. 6B depicts a close-up perspective view of the lower arm of FIG. 6 ;

FIG. 7 depicts a side view of a prior art cross arm;

FIG. 7A depicts a cross-sectional view of the web of FIG. 7 ;

FIG. 7B depicts stresses on the prior art cross arm of FIG. 7 when aload is applied;

FIG. 8 depicts a side view of a cross arm according to the presentdisclosure;

FIG. 8A depicts a cross-sectional view of the web of FIG. 8 ;

FIG. 8B depicts stresses on the cross arm of FIG. 8 when a load isapplied;

FIG. 9 depicts a side view of another prior art cross arm;

FIG. 9A depicts a cross-sectional view of the web of FIG. 9 ;

FIG. 9B depicts stresses on the prior art cross arm of FIG. 9 when aload is applied;

FIG. 10 depicts a side view of another cross arm according to thepresent disclosure;

FIG. 10A depicts a cross-sectional view of the web of FIG. 10 ;

FIG. 10B depicts stresses on the cross arm of FIG. 10 when a load isapplied;

FIG. 11 is a front perspective view of another embodiment of the presentdisclosure;

FIG. 12 is a closer-view of the installation of FIG. 12 , showingdetails of the arms;

FIG. 13 is a rear-perspective view of one of the arms of FIGS. 11-12 ;

FIG. 13A is a close-up perspective view of the arm of FIG. 13 ;

FIG. 14 depicts one of the stanchions of FIGS. 11-12 ;

FIG. 14A depicts a rear perspective view of the stanchion of FIG. 14 ;

FIG. 14B depicts a close-up of a mounting hole in the web of thestanchion of FIGS. 14-14A;

FIG. 15 depicts a side cross-sectional view of the installation of FIG.11 ;

FIG. 15A depicts a close-up side view of the top arm of FIG. 15 ;

FIG. 15B depicts a front perspective view of one of the other arms ofFIG. 15 ;

FIG. 16 depicts a side view of a prior art rack arm;

FIG. 16A depicts a cross-section of the prior art rack arm according toFIG. 16 ;

FIG. 16B depicts stresses on the prior art cross arm of FIG. 16 when aload is applied;

FIG. 17 depicts a side view of a rack arm according to the presentdisclosure;

FIG. 17A depicts a cross-sectional view of the web of FIG. 17 ;

FIG. 17B depicts stresses on the cross arm of FIG. 17 when a load isapplied;

FIG. 18 depicts a side view of another prior art rack arm;

FIG. 18A depicts a cross-section of the prior art rack arm according toFIG. 18 ;

FIG. 18B depicts stresses on the prior art cross arm of FIG. 18 when aload is applied;

FIG. 19 depicts a side view of another rack arm according to the presentdisclosure;

FIG. 19A depicts a cross-sectional view of the web of FIG. 19 ;

FIG. 19B depicts stresses on the cross arm of FIG. 19 when a load isapplied;

FIG. 20 depicts a side view of yet another prior art rack arm;

FIG. 20A depicts a cross-section of the prior art rack arm according toFIG. 20 ;

FIG. 20B depicts stresses on the prior art cross arm of FIG. 20 when aload is applied;

FIG. 21 depicts a side view of another rack arm according to the presentdisclosure;

FIG. 21A depicts a cross-sectional view of the web of FIG. 21 ;

FIG. 21B depicts stresses on the cross arm of FIG. 22 when a load isapplied;

FIG. 22 is a front perspective view of another embodiment of the presentdisclosure using flat-arm rack arms;

FIG. 23 is a less-encumbered view of FIG. 22 , showing details of theflat arms;

FIG. 23A is an upward view of FIG. 23 , revealing details of the stressattenuators of the flat rack arms of FIGS. 22 and 23 ;

FIGS. 24, 24A, 24B and 24C are more detailed views of the rack arms ofFIGS. 22-23 ;

FIGS. 25, 25A and 25B show details of stanchions that may be used withflat rack arms;

FIGS. 26, 26A and 26B show additional details of the rack arms in thisembodiment;

FIGS. 27 and 27A depict a side view and a cross-sectional view of acable rack arm without stress attenuators or ribs; FIGS. 27B and 27Cdepict stresses and a failure mode of this cross arm;

FIGS. 28 and 28A depict a side view and a cross-sectional view of a rackarm with a stress attenuator; FIGS. 28B and 28C depict stresses and afailure mode of the rack arm with the stress attenuator; and

FIGS. 29, 29A and 29B depict side and cross-sectional views of a rackarm having a stress attenuator and reinforcing ribs; FIGS. 29C and 29Ddepict stresses and a failure mode of the rack arm of FIG. 29 .

DETAILED DESCRIPTION OF THE DRAWINGS AND THE DISCLOSED EMBODIMENTS

Embodiments of the present disclosure are preferably molded fromnon-metallic or plastic materials. In this context, “plastic” materialsinclude any resinous, thermoset, or thermoplastic materials, includingmaterials that are reinforced, foamed, or otherwise altered, and whichare formed by molding. Thus, in one embodiment, nylon with short glassfibers is used to make strong, stiff, and environmentally-resistantstanchions and rack arms. Other embodiments may use less costlymaterials, such as polyethylene or polypropylene, for applications inwhich less strength is required. The plastic materials may also includeparticulate fillers, such as aluminum oxide or calcium carbonate, or anyother filler useful in plastics molding. Other additives, such as flameor fire retardant substances, may also be useful.

Underground cable racks face several constraints for successful service.One of these constraints is that the molded stanchions or postsgenerally include penetrations so that the stanchions or posts may beattached to the walls or surfaces of the manholes or other undergroundinstallations in which they are placed. If cable rack arms are notintegral with the stanchions, there are then more penetrations so thatthe rack arms may be installed, to hold cables for power orcommunications. Each such penetration may be considered as a stressconcentrator, a point in the structure at which stresses will be morelikely to cause failure.

In molded posts or stanchions, the effects of the stress concentratorsmay at least be minimized by molding in the penetrations or holes, suchas attaching and holding apertures. In this way, the well-known“skin-effect” of plastic non-metallic materials will apply, lesseningthe effect of the stress concentration. The skin-effect of as-moldedplastics means simply that there is a barrier layer of resin on thesurface, resistant to infiltration of water. Embodiments of the presentdisclosure mold in a number of important features to take advantage ofthe skin effect and to make the stanchions as useful as possible. Iffasteners are used in assembling or installing composite or plasticunderground cable racks, the fasteners may also be made of composite orplastic components, as will be seen below.

A first embodiment of the disclosure is depicted in FIG. 1 , whichdepicts an underground cable installation 10 with two molded stanchions11 a, 11 b. Stanchions 11 a, 11 b are installed in tandem as adjacentvertical columns. Stanchions 11 a, 11 b are desirably mounted adjacenteach other when there are a large number of cables to provide adjacentmutual support for each other.

Each column includes a stanchion 11 a, 11 b, and three supports 12, 14,16 for holding power and communication cables 18. Installation of cablesmay include insulation 19 or a conduit that encases the cables 18. Cablesupports 12, 14 may termed cable rack arms, while shorter support 16 maybe a U-shaped arm. Each rack arm 12, 14 may support a plurality of poweror communications cables, as shown. The cables may be secured to thearms with cable ties 17. Communications cables and power cables, securedto the stanchions by cross arms or by cable ties, are preferablyseparated from each other. Stanchions 11 a, 11 b may include holdingapertures 20 for installing cross arms, and attaching apertures 24, seeFIG. 4 , for bolting the stanchions to a wall or other structure in theunderground installation. While the stanchions and cross-arms are mostuseful for underground use, there is no reason why they cannot be usedin other applications, such as for aboveground or even mobile power orutility installations. As depicted in FIG. 2 , there are preferably twoholding apertures 20 straddling each attaching aperture 24, except atthe top of the stanchion, where there is a single attaching aperture 24for a single holding aperture 20. In FIG. 1 , stanchions 11 a, 11 b arebolted to a concrete wall 4 with bolts 6 at the top and bottom of thestanchion (bottom bolts not visible in FIG. 1 ). Additional bolts mayalso be used in the central portion of the stanchion.

A closer view of stanchion 11 a and its cable rack support arms is shownin FIG. 2 . Lower cross arm 12 is longer and able to support more poweror communications cables. Stanchion holding apertures 20 may berectangular with rounded corners, well known to those skilled in moldingarts, the corners preferably radiused from about 0.005″ to about 0.060″or more to avoid stress concentrations and cracking to the greatestextent possible. Holding apertures 20 preferably include a smallprojection 22 on one side of the aperture, for creating an interferencefit when cross arms 12, 14, 16 are installed. Upper cross arm 14 may beshorter than lower cross arm 12.

Lower cross arm 12 includes a horizontal upper portion 120, a lowerportion 122, a central portion 124 (see FIG. 6 ), and ribs 126 extendingfrom the upper portion 120 to the lower portion 122. The lower cross arm12 also includes a lip and a vertical mounting portion 128 for bearingagainst stanchion 11 a. Vertical mounting portion 128 may be considereda proximal end of the cross arm, this portion being nearest thestanchion in which it is mounted. The opposite end of the arm 12, nearlip 129, may be termed a distal end of cable rack arm 12. Upper crossarm 14 is also suitable for holding a plurality of power andcommunications cables. Upper cross arm 14 also include a horizontalupper portion 140, a lower portion 142, a central portion 144 (see FIG.6 ), and ribs 146 extending from the upper horizontal portion 140 to thelower portion 142. Upper cross arm 14 also includes a lip 149 and avertical mounting portion 148 for bearing against stanchion 11 a.Vertical mounting portion 148 may be considered a proximal end of thecross arm, this portion being nearest the stanchion in which it ismounted. The opposite end of the arm 14, near lip 149, may be termed adistal end of cable rack arm 14. Additional details of the interplay andrelationships between the central portion of the arms, the upper andlower surfaces, and the ribs will be depicted in later drawings.

As shown in FIG. 3 , upper cross arm 14 is shorter and may be suitablefor bearing a smaller number of cables. The cross arms may bemanufactured with brackets 30, as also shown in FIG. 3 . In thisembodiment, each cross arm is made with an upper bracket and anidentical lower bracket, although the brackets may be different in otherembodiments. As shown in FIG. 3A, each bracket 30 may include a supportportion 32 and an attaching portion 34 for interfacing with thestanchion and mounting the cross arm to the stanchion. In the embodimentof FIGS. 3-3A, the brackets also include a projection or dot 36 forcreating an interference fit with the holding aperture 20 and itsprojection 22. Projections may be a small, rounded dot 36 as shown onbracket 30 or may take on other forms. In FIG. 3A, bracket 30 has aprojection that includes a dot 36 and a continuation rounded rectangle38, which may be the same height as dot 36 or may be a lesser height. Inone embodiment, the projections have a maximum height of 0.075 inches (2mm); in other embodiments, the maximum height may be about 0.050 inches(1.2 mm). Other heights may be used.

The purpose of the projections is to create a slight interference fitand to reduce play when the cross arm is installed into a stanchion. Thecross arm can bridge two stanchions. In this embodiment, cross arm 12has two different projections, one of which is dot 36 and the other ofwhich is dot 36 and continuation 38. The interference fit may occur onlywhen the cross arm is being assembled, or the interference fit may bedesigned to continue after assembly. If interference continues afterassembly, the joint may be known as a “friction fit.” As may be seen inFIGS. 3 and 3A, there is preferably a longer projection 38 on at leastone bracket of each cross arm to provide an interference fit for theassembly of the cross arm into the holding apertures. The heights of theprojections on both the brackets and the apertures are chosen so that aperson assembling the arm to the stanchion must exert effort to overcomethe interference to complete the assembly. Once assembled, however, theinterference will resist forces tending to cause disassembly, such asloads on cross arms and rocking of the stanchions in place.

Such friction fits tend to increase the stability of the joint andresist upward movement of the cross arm. This resistance is important,because many communications cables use splice cases to enclose sectionswhere the cables are spliced together (not shown). Splice cases aretypically rectangular or cylindrical in form, may be from seven totwelve inches (about 188 mm to 305 mm) in diameter, or more, and may beup to three feet or more in length. Splice cases are typically moldedfrom plastic materials, or fabricated from stainless steel, or acombination of both. Splice cases are filled with pressurized air toresist ingress of water, and may thus be lighter than water. Splicecases are typically anchored to cross-arms, so that when a manhole fillswith water, the buoyant splice cases can create an upward load on thecross-arms, tending to lift the cross arms from the stanchions or postsand helping to hold the arms in place. Friction fits reduce thelikelihood that the cross arms will be lifted out of the stanchions,allowing the splice cases and cables to fall to the ground when thewater eventually drains from the manhole.

FIG. 4 depicts the front portion of stanchion 11 a and FIG. 4A depictsthe reverse side of stanchion 11 a, with front and reverse views ofholding apertures 20, attaching apertures 24 and pockets 26 forreceiving portions of a locking barb 50. As best seen in the lower ormiddle portion of FIG. 2 , a locking barb 50, see FIG. 5 , may beinstalled in the upper portion of the space remaining in aperture 20after cross-arms 12, 14, 16 are mated with stanchion 11 a. Stanchions 11a, 11 b may also include recesses (not shown) for attaching cables 18,19 by means of cable ties 17. The recesses and the wall to which thestanchion is attached create an aperture through which the cable tie isthreaded. Locking barbs 50 may be considered to be fasteners becausethey aid in the assembly of these mechanical parts and help to hold thearms in place.

As shown in FIG. 4 , the attaching apertures 24 may be molded incircular or elliptical form, to easily distinguish attaching apertures24 from holding apertures 20. In other embodiments, their shapes may bereversed, or may be the same, or may take on other shapes as desired.FIG. 4B depicts a close-up view of holding aperture 20 with projection22, which reduces the space available in holding aperture 20 and mayhelp in creating an interference fit. In one embodiment, projection 22is a rounded or half-cylinder with a maximum height of about 0.075inches (2 mm). Other shapes and other maxima may be used instead. Thestanchion also includes circular or elliptical attaching apertures 24,used for attaching the stanchion to a nearby installation feature, suchas a wall. Attaching apertures 24 may include recesses 24 a for holdinga washer or a bolt head used to fasten the stanchion to a wall. For allbut the top-most attaching aperture on each stanchion, there are twoholding apertures 20 for each attaching aperture 24.

When the locking barb 50 is bent and fully installed in aperture 20between the upper surface of the upper arm bracket and the upper edge ofthe stanchion holding aperture, locking barb 50, which was compressedduring the insertion procedure, opens, causing the upper surface ofupper flange 50 a to press against the upper edge of the holdingaperture 20, the lower surface of lower flange 50 c to press against theupper face of the upper arm bracket 36, and the barbs 50 d to latch intopockets 26 provided on the rear of the stanchions, as shown in FIG. 4A.The latching of the barbs into the pockets secures locking barb 50 inthe stanchion holding aperture, and also secures the rack arm to thestanchion.

Stanchions 11 a, 11 b may be molded in various sizes, such as differentlengths or widths, and with other features deemed desirable for theiruse. Thus, stanchions 11 a, 11 b may be molded in standards sizes, suchas 2 feet (24 inches long) or 3 feet (36 inches long), 3 inches or 4inches wide, and 1″ thick. Other lengths, widths, or depths may be usedas desired, including metric sizes. In order to minimize the number oftools necessary to please a large number of customers, the stanchionsmay also be designed for custom tailoring. Thus, it is preferable thatstanchion embodiments of the present disclosure may be field cut withoutlosing all the benefits of a molded product, e.g., the skin effect ofmolded non-metallic or plastic materials, resisting infiltration ofmoisture.

The stanchions are designed so that the distance between adjacentholding apertures 20 is equal to or very close to the distance betweenbrackets in the cross arms discussed above. This distance, from thebottom of one holding aperture to the bottom of the adjacent holdingaperture, is known as the vertical adjustment. In instances where twostanchions are joined, the stanchions are designed so that the distancebetween the top holding aperture in the bottom stanchion and the bottomholding aperture in the top stanchion is also equal to or very close tothe distance between brackets in the cross arms. This allows for readyinstallation of cross arms in a single stanchion, and also in joined ortandem stanchions. It has also been discovered that using the cross armto bridge two stanchions in this manner adds to the stability of theassembled stanchions. Although a fastener or bolt and the male andfemale joining portions provide the primary support for joining thestanchions, the cross arm also serves to stabilize the two joinedstanchions.

FIG. 2 also depicts the use of a locking barb 50 to positively lock arms12, 14, 16 into apertures of stanchion 11 a. The upper bracket of thecross arm and locking barb 50 described above fit into a holdingaperture 20. Locking barb 50 is molded from relatively stiff plastic,such as polycarbonate, and may include stiffeners, such as glass fibers,so that locking barb 50 has a high spring constant and requires aconsiderable effort to bend flanges 50 a, 50 c about center 50 b.

When the locking barb is bent and fully installed in aperture 20 betweenthe upper surface of the upper arm bracket and the upper edge of thestanchion holding aperture, locking barb 50, which was compressed duringthe insertion procedure, opens, causing the upper surface of upperflange 50 a to press against the upper edge of the holding aperture 20,the lower surface of lower flange 50 c to press against the upper faceof the upper arm bracket 36, and the barbs 50 d to latch into pockets 26provided on the rear of the stanchions, as shown in FIG. 4A. Thelatching of the barbs into the pockets secures locking barb 50 in thestanchion holding aperture.

Vertical block 50 e is located in the center of the locking barb and isan integral part of the locking barb, providing the positive lock andpreventing the arm from coming out of the stanchion under load. Lockingbarb 50 is removable and reusable. To remove the locking barb, the userpresses down with some effort on upper flange 50 a, causing barbs 50 dto disengage from the pockets in the rear of the stanchion, andpermitting locking barb 50 to be withdrawn from the stanchion holdingaperture. The spring need not take on the shape depicted in FIGS. 2 and5 , but may take on any convenient shape for providing a compressiveload to resist disassembly.

Closer views of the new disclosure are seen in FIGS. 6, 6A, 6B, 7, 7A,7B, 8, 8A, 8B, 9, 9A, 9B, 10, 10A and 10B. FIG. 6 depicts a side view ofthe underground cable installation 10. Stanchion 11 a is secured to aconcrete wall 4 with bolts (not seen in FIG. 6 ). As previously shown inFIGS. 1 and 2 , the installation includes lower cross arm 12, middlecross arm 14 and upper U-shaped arm 16. Lower cross-arm 12 includes anupper flanged portion 120, a lower flanged portion 122, a web 124connecting the upper flanged surface to the lower flanged surface andlip 129, on a distal portion of arm 12. Vertical portion 125 on theproximal end of cross arm 12 is part of the interface of arm 12 withstanchion 11 a. A series of reinforcing ribs 126 also extends from theupper surface to the lower surface. The web 124 is typically narrow inwidth, a nominal width, while the ribs typically, but not in allinstances, extend from the upper surface or right side to the lowersurface for the entire width of the upper and lower surface,respectively, as shown in FIG. 2 . In FIG. 6 , lower cross arm 12supports four power or communications cables 18 with insulation 19. Thecables may be secured to the cross arm with one or more cable ties 17using the orifices 132 in the web of the cross arm.

Middle cross arm 14 also appears in FIG. 6 , supporting three power orcommunication cables 18 with insulators or conduits 19. Cross arm 14includes an upper flanged surface 140, a lower flanged surface 142, aweb 144 connecting the upper flanged surface to the lower flangedsurface and lip 149, on a distal portion of arm 14. Vertical portion 145on the proximal end of the cross arm is part of the interface of the armwith stanchion 11 a. A series of reinforcing ribs 146 also extends fromthe upper surface 140 or the right side to the lower surface 142. Theweb 144 may be narrow in width, a nominal width, while the ribs 146typically extend fully from the upper surface to the lower surface forthe entire width of the upper and lower surface, respectively, as alsoshown in FIG. 2 . As shown for both cross arms 12, 14, cable ties 17 maybe used to secure the cables to the cross arms. Middle cross arm 14 alsohas a series of orifices 152, which may be used with the cable ties tosecure the cables to the rack arm. Upper U-shaped arm 16 also has anorifice 16 a which may be used to tie down a power or communicationscable 18 and its insulation 19.

A closer look at portions of cross arm 14 and cross arm 12 is seen inFIGS. 6A and 6B. In elevation view FIG. 6A, cross arm web 144 hasapertures or openings 152 between ribs 146. The openings may be about aquarter-inch (6 mm) in width, or may BE wider or narrower. The openingsmay be about one inch (25 mm) long, or they may be longer or shorterthan one inch. As seen in FIGS. 6, 6A and 6B, the openings or orificesmay be parallel to a top surface of the cross arm. One or more cableties 17 may be used to secure the cables and conduits or insulation tothe cross arm 14. The cable ties may be plastic and may be secured usinga fastener 17 a, which may be an integral fastener. Outer portion 152 aof aperture 152 is thicker than the web into which the aperture fits.Outer portion 152 a is thicker than the nominal width of web 144. In oneembodiment, web 144 is 5/16 inches (8 mm) thick, and the outer portionof 152 a is 19/32 inches (15 mm) thick, about twice the thickness of web144. FIG. 6B is a perspective view of lower cross-arm 12, this viewshowing better the thickness difference between web 124 with a nominalthickness and the outer reinforcement 132 a of orifice or aperture 132.As discussed above in FIG. 6A, one or more apertures may be made betweenribs 126 of the cross arm. The increased thickness of the reinforcementhas been found to reduce the stresses on the arms 12, 14, 16 when theyare subjected to stress.

It may be important to smooth all transitions between portions of thecross arms, such as cross arms 12, 14. Any changes in part shape orthickness should be generously radiused, so that there are no sharpcorners or abrupt transitions. Corner radii of 1/16 inches or 3/32inches may be used. Other corner radii may be used. In one example, thetransition from the outer portion of the stress attenuator to the mainbody of the web are also radiused, e.g., 1/16 inches or 0.0625 inches(1.6 mm). As seen in FIG. 6A for cross arm 14, there are dimensionaltransitions 154 between the lower flange 142 and web 144, between web144 and ribs 146, and between web 144 and orifice 152 and its outerreinforced portion 152 a. The same holds true for cross arm 12 in FIG.6B. There should be generously radiused transitions 134 between web 124and lower flanged portion 122, between web 124 and ribs 126 and betweenweb 124 and orifices 132 and their outer reinforced portions 132 a. Insome embodiments, the outer portions 132 a, 152 a may only be slightlywider than their adjacent flanges, i.e., the thickness of the cross armweb 124, 144. In other embodiments, the outer portions may be twice asthick as the adjacent flange, i.e., the thicknesses of the web intowhich the orifices are placed.

The situation may be better understood with reference to FIGS. 7, 7A and7B. FIG. 7 depicts a standard RA-20 LP prior art cross arm 70 with ahorizontal upper flange 71, lower flange 72, web 73, ribs 74, verticalside portion 75, angled interface brackets 76, 76 a, and horizontalinterface guide 77. Arm 70 also has a lip 79 on a distal end of the arm,while vertical side portion 75, angled brackets 76 and horizontal guide77 are positioned on a proximal end of the arm, forming an interfacearea of the arm, for interfacing with a stanchion into which the armwill be assembled. Note that the top angled bracket 76 has a “dot”interference feature and the lower angled bracket 76 a has the “dot”interference feature and a projection cylindrical interference feature.It is possible that one more ribs 74 a do not extend all the way fromlower flange 72 to horizontal upper flange 71. Cross arm 70 may includeone or more apertures or orifices 78 that are suitable for use withcable ties (not shown). FIG. 7A is a cross-sectional view of FIG. 7 .The orifice 78 is depicted in FIG. 7A as an opening in web 73, depictedhere as having a uniform, nominal thickness. In testing, it was foundthat the prior art arm could withstand a maximum load of 1300 pounds 79a placed just inside lip 79 on the upper flange. Finite element analysis(FEA) showed that this resulted in a point of maximum stress of 24 ksiat a point 79 b on the outer portion of the outer-most orifice 78. Theload, stress and deflection are shown graphically in FIG. great.

The present disclosure may be better understood with reference to FIGS.8, 8A and 8B. FIG. 8 depicts an improved RA-20 LP cross arm 80 accordingto the present disclosure in which the apertures or orifices have beenreinforced by increasing the thickness of the web surrounding theapertures. Cross arm 80 includes a horizontal upper flange 81, lowerflange 82, web 83, ribs 84, vertical side portion 85, angled brackets86, 86 a, horizontal guide 87 and tie-down apertures or orifices 88. Arm80 also has a lip 89 on a distal end of the of the arm, while verticalside portion 85, angled brackets 86, 86 a and guide 87 are positioned ona proximal end of the arm, for interfacing with a stanchion into whichthe arm will be assembled. Note that the top angled bracket 86 has a“dot” interference feature and the lower angled bracket 86 a has the“dot” interference feature and a projection cylindrical interferencefeature. It is possible that one more ribs 84 a do not extend all theway from lower flange 82 to horizontal upper flange 81. As notedpreviously, one or more of the apertures or orifices 88 are suitable foruse with cable ties (not shown).

FIG. 8A is a cross-sectional view of FIG. 8 , depicting upper flange 81,lower flange 82, web 83 and orifice 88. The nominal thickness of web 83is increased at the areas where the web transitions to an orifice, areas83 a. As seen in FIGS. 8 and 8A, at least one rib 84 may extend fromupper flange portion 81 to lower flange 82, intersecting with theportion of the web 83 a having a thickness greater than the nominalthickness of the web. Thus, in some embodiments, the thickness of thetransition area 83 a may be twice as thick as web 83 itself. In otherembodiments, the transition areas may be only slighter thicker, withperhaps a 10-25 percent increase in thickness. Other embodiments mayhave a thickness increase from 25 percent to 75 percent, or at least a90% increase in thickness, or a 100% increase in thickness. Yet otherembodiments may have a transition area that is more than twice as thickas the web, i.e., an increase of more than 100%. As can be seen in FIG.8A, the increase in thickness of the web 83, i.e., the stress attenuator83 a, is distributed equally on both sides of the web. Other proportionsmay be used.

Note that when arm 80 is molded, it is important that internal corners83 b are rounded or radiused, as well as external corners 83 c, such asthose formed about orifice area 83 a. Thus, where the wider web portion83 a meets web 83 having nominal thickness, the internal corner 83 bshould be radiused. In a similar manner, external corners 83 c shouldalso be rounded. Note that areas of web 83 with a nominal thickness havea rectangular cross section. In one embodiment, internal and externalcorner radii of 3/32 inch (0.09375 inches or 2 mm) may be used; inanother embodiment, corner radii of 1/16 inch (0.0625 inches or 1.6 mm)may be used. Other corner radii, internal and external corners, may beused. Different internal and external corner radii may be used.

In testing, it was found that the improved arm could withstand a maximumload of 1800 pounds 89 a placed just inside lip 89 on the upper flange.Finite element analysis (FEA) showed that this resulted in a point ofmaximum stress of 24 ksi at a point 89 b on the outer portion of theouter-most orifice 88. The load, stress and deflection are showngraphically in FIG. 8B.

Note by comparison, the prior art arm of FIGS. 7, 7A and 7B couldwithstand only 1300 pounds of force. Further testing with the stressattenuator's increased thickness, showed that if the force applied was1300 pounds, the point of maximum stress remained the same, but with amaximum stress of 17 ksi, an improvement (stress reduction) of 1 minus17 ksi divided by 24 ksi, equal to 0.29, which multiplied by 100%,equals 29%. Accordingly, an increased interface thickness may beconsidered a stress attenuator. Alternatively, for a given maximumstress, say 24 ksi, the stress attenuator feature may be considered toincrease the load-bearing capacity of the arm, in this case from 1300lbs. to 1800 lbs. This is an increase of 38 percent, a significantincrease.

An additional example is given in FIGS. 9, 9A and 9B. FIG. 9 depicts astandard prior art cross arm 90, a shorter cross arm termed an RA-14 LP.Cross arm 90 includes a horizontal upper flange 91, lower flange 92, web93, ribs 94, vertical side portion 95 and angled brackets 96, 96 a. Arm90 also has a lip 99 on a distal end of the arm, while vertical sideportion 95 and angled brackets 96, 96 a are positioned on a proximal endof the arm, forming an interface area of the arm, for interfacing with astanchion into which the arm will be assembled. Note that the top angledbracket 96 has a “dot” interference feature and the lower angled bracket96 a has the “dot” interference feature and a projection cylindricalinterference feature. Cross arm 90 may include one or more apertures ororifices 98 that are suitable for use with cable ties (not shown). FIG.9A is a cross-sectional view of FIG. 9 . The orifice 98 is depicted inFIG. 9A as an opening in web 93, which is depicted here as having anominal, uniform thickness. In testing, it was found that the prior artRA-14 LP arm could withstand a maximum load of 1300 pounds 99 a placedjust inside lip 99 of the upper flange 91. Finite element analysis (FEA)showed that this resulted in a point of maximum stress of 37 ksi at apoint 99 b on the inner portion of the outer-most orifice 98. The load,stress and deflection are shown graphically in FIG. 9B. As noted above,internal and external corners 98 a should be rounded and generouslyradiused.

The present disclosure may be better understood with reference to FIGS.10, 10A and 10B. FIG. 10 depicts an RA-14 LP cross arm 100 according tothe present disclosure in which the areas surrounding the apertures ororifices have been reinforced by increasing the thickness of the websurrounding these apertures. Cross arm 100 includes a horizontal upperflange 101, lower flange 102, web 103, ribs 104, vertical side portion105, angled interface brackets 106, 106 a. Arm 100 also has a lip 109 ona distal end of the of the arm, while vertical side portion 105, andangled brackets 106, 106 a are positioned on a proximal end of the arm,for interfacing with a stanchion into which the arm will be assembled.Note that the top angled bracket 106 has a “dot” interference featureand the lower angled bracket 106 a has the “dot” interference featureand a projection cylindrical interference feature. As noted previously,cross arm 100 may include one or more apertures or orifices 108 that aresuitable for use with cable ties (not shown) for securing power andcommunications cables.

FIG. 10A is a cross-sectional view of FIG. 10 , depicting upper flange101, lower flange 102, web 103 and orifice 108. The nominal thickness ofweb 103 is increased at the areas where the web transitions to anorifice, areas 103 a. As seen in FIGS. 10 and 10A, at least one rib 104may extend from upper flat portion 101 to lower flange 102, intersectingwith the portion of the web 103 a having a thickness greater than thenominal thickness of the web. In this instance, the left-most ribintersects with two ribs extending between the upper flange 101 (top)and the lower flange 102 (bottom) of the arm. Thus, in some embodiments,the thickness of the transition area 103 a may be twice as thick as thenominal thickness of web 103 itself. In other embodiments, thetransition areas may be only slighter thicker, with perhaps a 25-50percent increase in thickness. Other embodiments may have a thicknessincrease from 50 percent to 100 percent. Yet other embodiments may havea transition area that is more than twice as thick as the web, i.e., anincrease of more than 100%. As noted previously, all transitions orcorners in the web, such as corners 103 b, 103 c and its transitionsshould be gently radiused to avoid sharp corners and abrupt transitions.This helps to prevent stress concentration cracking in stressed areasand insures longer useful lives for this equipment.

As stated, FIG. 10 depicts an improved cross arm RA-14 LP of the presentdisclosure. In testing, it was found that the arm could withstand amaximum load of 2000 pounds 109 a placed just inside lip 109 of theupper flange. Finite element analysis (FEA) showed that this resulted ina point of maximum stress of 37 ksi at a point 109 b on the innerportion of the outer-most orifice 108. The load, stress and deflectionare shown graphically in FIG. 10B. Note by comparison, the prior art armof FIGS. 9, 9 a and 9B could withstand only 1300 pounds of loading.Further testing with the increased thickness of the stress attenuatorshowed that if the load applied was 1300 pounds, the point of maximumstress remained the same, but the maximum stress was 24 ksi, animprovement (stress reduction) of 1 minus 24 ksi divided by 37 ksi, thatis, 0.35, which multiplied by 100%, equals 35%. Accordingly, and asnoted above in the examples for the RA-20 LP arm, increasing theinterface thickness of the web may be considered a stress attenuator.Alternatively, for a given maximum stress, say 37 ksi, the stressattenuator feature may be considered to increase the load-bearingcapacity of the arm, in this case from 1300 lbs. to 2000 lbs. This is anincrease of 54 percent, and may well give a longer life for the use ofthis equipment.

As discussed above, embodiments of the cable arms described herein arepreferably molded from plastic or composite materials. In this context,such materials include any resinous, thermoset, or thermoplastic matrixmaterial, including materials that are reinforced or otherwise altered,and which are formed by molding. In one embodiment, nylon with shortglass fibers is used to make strong, stiff, andenvironmentally-resistant rack arms. In the present context, short glassfibers means glass fibers from about ⅛″ (about 3 mm) long to about ¼″(about 6 mm) long. Long glass fibers, from about 3/16″ (about 5 mm) toabout ⅜″ (about 10 mm) may be used instead. Medium-length glass fiberreinforcements may also be used. Other embodiments may use less costlymaterials, such as polyethylene or polypropylene, for applications inwhich not as much strength is required. The plastic materials may alsoinclude particulate fillers, such as aluminum oxide or calciumcarbonate, or any other filler useful in plastics molding, such as fireretardant additives or flame-retardant additives. Glass fibers withdiameters from about 0.009 mm (0.00035 in) to about 0.011 mm (0.00043in) may be used for reinforcement. Fibers with other diameters may alsobe used.

In addition to cable arms, the stanchions may also be molded fromnon-metallic materials. Stanchions may be injection molded,thermoformed, transfer molded, compression molded, or even pultruded.Typical polymers or resins include polyester, such as standardpolyester, fire-retardant polyester, vinyl ester and fire-retardantvinyl ester. In addition to a thermoplastic or thermoset resin, thestanchions may include a reinforcement, such as glass fibers. Parts thatare discretely molded, one at a time, may include chopped or short glassfibers, as mentioned above. Those parts or parts that are pultruded mayalso be made with unidirectional fiberglass roving, continuous strandmultidirectional glass fiber mat and stitched woven fiberglass roving.The reinforcements add longitudinal and transverse strength andstiffness. In one embodiment, a stanchion may have a single layer ofpultruded composite. In another embodiment, the stanchion may have anadditional layer, such as a first layer with a reinforcement transverseto a direction of pultrusion and a second layer parallel to thedirection of pultrusion. In one embodiment, the first layer may betransverse plus or minus fifteen degrees to a direction of travel of thepultrusion. An outer surface veil mat may also be used to add UVresistance and hand-friendliness to the resin-rich surface. If greaterstrength or stiffness is desired, carbon fiber reinforcement may also beused in addition to or in lieu of glass fiber. Some of the embodimentsdiscussed below may advantageously made from pultruded plasticmaterials.

In one embodiment, pultruded C-channels are made with about from about30 to about 40 weight %, e.g., 33%, unidirectional fiberglass roving andabout 10 to about 25 weight %, e.g., 17%, continuous multidirectionalglass fiber mat. Higher or lower loadings of reinforcement may be used.The mat is believed to especially increase the strength and stiffness ofthe corners of the pultrusion. In other embodiments, unidirectionalroving is stitched together with transverse glass or cotton fibers toform a stitched woven fiberglass roving. The stitching helps to orientand control the roving and make it easier to pull into the tooling. Theproportion of the reinforcements may vary within reasonable limitsconsistent with the desired strength and stiffness, e.g., from about 35%to 65%, or even higher. In other embodiments, only the continuousmultidirectional glass fiber mat may be used. In still otherembodiments, other forms and orientations of reinforcement may be used.All are intended to be within the scope of the present disclosure. A fewspecific embodiments are discussed below with reference to FIGS. 11-15 ,et. seq.

The pins, fasteners, used to mount the cable rack arms to stanchions mayalso be molded from plastic materials. The pins are desirably injectionmolded, but they may also be compression molded, pultruded and/ormachined. It will be clear to those with ordinary skill in the art thatthe pins support a shear load caused by the cable rack arm and thecables loaded onto the arm. Accordingly, reinforcements, such as glassfibers, that are longitudinally oriented in the direction of the shaftof the pin, will be helpful in supporting the load and resistingdeformation. This may be achieved by using glass-reinforced plasticmaterials. The desired orientation may also be achieved by using widergates in injection molding the pins. It has also been found duringexperiments that molding the pin with a reservoir, attached to the endof the pin opposite the gate with a small orifice, causes additionalplastic flow and helps to orient the fibers in the direction of flow,during the injection molding process. Pins used to attach cable rackarms to a stanchion are considered fasteners because they aid in themechanical assembly of the cable rack arm to the stanchion.

Underground cable racks face several constraints for successful service.One of these constraints is that the stanchions or posts generallyinclude penetrations in both the stanchions and the arms so that thestanchions or posts may be attached to the walls or surfaces of themanholes or other underground installations in which they are placed. Ifcable rack arms are not integral with the stanchions, there are thenmore penetrations so that the rack arms may be installed, to hold cablesfor power or communications. Each such penetration may be considered asa stress concentrator, a point in the structure at which stresses willbe more likely to cause failure.

Additional embodiments of the disclosure are depicted in FIG. 11 , whichdepicts an underground cable installation 111 with two stanchions 112secured to concrete wall 4 via bolts (bolts not visible in FIG. 11 ).The stanchions may be existing metallic stanchions, such as doubleflange steel stanchions (see FIG. 12 ) or single flange steel stanchionsfitting into groove 130 e (see FIG. 13 ). Alternatively, the stanchionsmay be non-metallic, such as non-metallic C-channel stanchions 112. Inthis instance, each stanchion is used to mount a first cable rack arm114, three cable rack arms 116, and final cable rack arm 118. Cable rackarm 114 has four position places or saddles on the top portion of therack arm for mounting power or communications cables 18 along with aconduit or insulation 19. Each cable rack arm 116 has three positionplaces or saddles on top for mounting cables. The final cable rack arm118 has two position places for mounting cables. Of course, otherembodiments may have only a single mount or may have additional mounts,such as an arm with a five mounts or saddles. Further, some embodimentsmay require that the top surface of the arm be flat. One advantage ofthe embodiments depicted herein is that the mounts or saddles are formedintegrally with the rack arms themselves. Thus, in these embodiments, noadapters or additional parts need to be assembled before installing andusing the rack arms. The portions of the rack arms nearest the stanchionare referred to as the proximal portions, while the portions of the rackarms farthest removed from the stanchion are the distal portions. Theproximal portions of the rack arms form an interface for mounting to thestanchion.

A closer perspective view of the installation is depicted in FIG. 12 ,showing pultruded plastic stanchion 112 with the cable rack armsdescribed above with reference to FIG. 11 . The stanchion is secured tothe concrete wall (not shown) via one or more bolts 6 using holes orapertures (see FIGS. 14, 14A and 14B) that are molded into thestanchion. Alternatively, the holes or orifices could be machined orstamped into the stanchions. FIG. 14 is a front perspective view ofstanchion 112, FIG. 14A is a rear perspective view of the stanchion.Stanchion 112 has a C-shaped cross section formed by web 112 a andflanges 112 b on either side of web 112 a. The stanchion flanges mayalso have openings or orifices 112 c for mounting cable rack arms. Theweb 112 a may include orifices or openings 112 d for mounting to amounting surface, such as a concrete wall, via bolts as discussed above.FIG. 14B is a close-up view of mounting orifice 112 d, having an ovalshape, for mounting the stanchion to a wall or other mounting surface.The rack arms 114, 116, 118 are mounted to channel stanchion 114 viamounting pins 113 a, secured with cotter pins 113 b. The proximal orinterface portion of the rack arms 114, 116, 118 include mounting holesor orifices for mounting pins 113 a so the pins can secure the rack armsto stanchion 112.

The close-up view of FIG. 13 provides details of the configuration ofmount arm 130, which may be the same as mount arm 116 or may bedifferent. Cable rack arm 130 has a proximal portion 130 a, for theportion of the rack arm that when mounted will be nearest to thestanchion, and a distal portion 130 b, which will be mounted away fromthe stanchion. The cable rack arm 130 has an upper portion 132 and alower portion 138, the upper and lower portions acting as flanges thatare connected via central web 131. Web 131 has a nominal thickness inmost areas of arm 130. The cable rack arm thus has a cross section witha web and flanges, akin to an I-beam or an H-beam, and has increasedsection modulus and strength. This increased stiffness or strength makescable installations more stable and reliable. In addition, a number ofribs 137 extend between the lower portion 138 and the vertical portion135 or the upper portion 132. These ribs help to strengthen and stiffenthe rack arm for supporting what can be very heavy loads from powerand/or communications cables. Cable rack arm 130 also has threehorizontal tie-down openings or orifices 133, in which the thirdorifice, nearest the proximal end 130 a, is only partly visible in FIG.13 . These orifices or openings may be used in conjunction with cableties or other suitable fasteners to secure power or communicationscables, or both, to the rack arm. Note that the areas of the web 131immediately adjacent openings 133 are considerably thicker than theremainder of the web. See FIGS. 13, 13A, 15 and 15B.

Upper portion 132 in this embodiment includes three cable rack saddlesor mounts 134, the mounts separated by upper flat surfaces 136. Upperportions of the ribs may extend from the undersides of the upper flatsurfaces 136, from the undersides of the cable rack mounts 134 or fromthe vertical portion 135. The ribs extend to the lower portion 138.Lower portion 138, further described below, is mounted at an acute angleA to the upper portion surface 132. The angle is less than 90°, anddesirably less than 60°. The imaginary apex of the angle will be to theright of the mount arms, as also shown in FIG. 13 . In practice, angle Amay range from about 15 degrees to about 47 degrees, from 10 degrees toabout 50 degrees, or from about 20 degrees to about 30 degrees.

FIG. 13 also depicts the proximal portion 130 a of the rack arms, theproximal portion being the end for use near the stanchion. The distalportion 130 b is the end of the arm away from the stanchion. Theproximal portion includes a rear surface vertical portion 135, a portionof which is flat and may be formed at an obtuse angle B to the flats 136on the top portion 132, an obtuse angle being an angle greater than 90°.The obtuse angle of these flats on the rear or proximal surface preventsdownward rotation of arm 130 past the point where the material of therear surface meets the inner surface of the channel 112. The obtuseangle B in one embodiment is about 91.5 degrees and may range from about90.5 degrees to about 95 degrees in practice, although other angles maybe used, such as a right angle or an acute angle. Having angle B at91.5° results in the flats 136 and the saddles 134 having an upward tiltof 1.5°. This upward tilt compensates for the deformation of the armwhen it is under load by very heavy power and communication cables.Thus, rack arm 130 will be biased to some extent for upward tilting ofthe rack arm on its distal end, near angle A. In other embodiments, itmay be desirable for the rack arm top surface 136 and saddles 134 to beat a nominal angle different from horizontal (90°). Thus, otherembodiments may include cable rack arms designed for an orientation of30°, 45°, 60° or other angle from horizontal. These angles may be usefulfor maintenance of the cables after installation.

Additional details of rack arm 130 are seen in FIG. 13 , which is aclose-up view of the rack arm. Proximal portion 130 a also includes slot130 e, separating the proximal portion into two halves. Slot 130 eprovides space that allows cable rack arm 130 to accommodate a singlewall stanchion, not shown, as opposed to a C-shaped stanchion, for easymounting. The halves on either side of slot 130 e each includes amounting hole 139. The holes thus allow insertion of a mounting pin,such as mounting pin 113 a, and its securing cotter pin 113 b, throughmounting holes 112 c of the stanchion 112, as well as the cable rack arm130 itself. Rack arm horizontal mounting holes 139 in this embodimentare below the top surface of the rack arm 130. In other embodiments, themounting holes 139 of proximal portion 130 a may be molded above the topsurface 136. In yet other embodiments, mounting holes 139 may be moldedsuch that the center of the horizontal orifices 139 are above the topsurface 136 of upper portion 132. The mounting holes 139 are used in alltypes of stanchions, while the slot 130 e is typically needed only for asingle-flange steel stanchion, a TEE-bar stanchion, an L-angle stanchionand an E-channel stanchion (none of these shown), but not a C-channelstanchion.

The cable rack arm embodiments described herein can be used for existingdouble flange steel stanchions as described and may also be used fornon-metallic C-channel, L-angle, TEE-bar or E-channel stanchions. Eachslot 130 e or interface also includes a void or relief 117 (see FIG. 12), the relief in the shape of about a 45-degree angle to the top of therack arm at the top of the slot and visible from the distal end of therack arm. Thus, in one embodiment, the interface or proximal portion ofthe rack arm includes contiguous mounting holes 139, slot 130 e andrelief 117. When the arm 130 is attached to a double flanged stanchion,a TEE-angle stanchion, an L-angle stanchion, or an E-channel stanchion,relief 117 allows upward rotation of the rack arms from their deployedhorizontal position as depicted in FIGS. 11-12 .

In other embodiments, the angle between the top surface and the rear orproximal side may be close to 90°, that is, a right angle. In theseembodiments, the cable rack arm may be viewed as a three-dimensionalright triangle, with the long side or hypotenuse being the angled sideon the bottom, that is, the bottom or lower portion. The top or longerportion is the major cathetus of the triangle and the side or shorterportion forms the minor cathetus of the triangle. The sides of thetriangle may be connected by a web, a web with ribs, or a gusset. Inthis patent, the terms major cathetus and minor cathetus intend the topand side portions of a cable rack arm, respectively, whether or not theangle between them is a right angle.

A closer, rear perspective view of the cable rack arm 130 is depicted inFIG. 13A. Cable rack arm 130 and lower portion 138 include a proximalportion 130 a, for placement nearer the mounting stanchion. As notedabove, slot 130 e separates the proximal portion 130 a into left andright halves 130 c, 130 d with flat portions 130 f, 130 g, respectively.In FIG. 13A, rhomboid sections 130 h and 130 j may be molded flat to fitsnugly against C-channel, TEE bar, L-angle and E-channel stanchions onwhich the cable arm is mounted. These are the flat sections discussedabove that may be oriented from about 90.5 to 95 degrees to the plane ofthe top surface of the cable arm. Side reliefs 130 k, 130 l allow use ofthe adjustable cable rack arms in existing double flange stanchionshaving substantial weld formations that would otherwise interfere withtheir installation, e.g., stanchion mounting bolt clearance. The cablerack arm 130 is wider nearer proximal end 130 a than its distal end 130b.

Downward rotation of the arm 130 may be stopped by surfaces 130 h, 130j, heel stops, when the arm is attached to a C-channel stanchion. In thecase of L-angle, TEE-bar, or E-channel stanchions, the heel stops ofeither or both surfaces 130 h, 130 j may be used to stop downward armrotation. With single-flange stanchions, such as the older single-flangestanchions, the end of slot 130 e may act as a heel stop for the cablerack arm. See FIG. 24A, which depicts slot 223 e ending in thenon-metallic material from which the rack arm is made. The end of theslot acts as the heel stop, and this will also apply to rack arms suchas those depicted in FIGS. 12-13A and FIGS. 15, 16, 17, 18, 19, 20, 21,23 and 23A.

A closer look at an installation of the rack arms 114, 116, 118 isdepicted in FIGS. 15, 15A and 15B. In these views, pultruded stanchion112 is intended for mounting to a concrete wall or other suitablemounting. Visible is the right flange of stanchion 112, with one orifice112 c visible near the top of the stanchion, and with five otherorifices not visible because each is filled with a mounting pin 113 aand its cotter pin 113 b. In this installation, a bottom A4 arm 114includes four mounting saddles 134 a near top portion 132 a, and alsoincludes four reinforced orifices 133 a. Arm 114 has a web 131 a with anominal thickness in most areas of the web. Portions 114 a of the web131 a nearest the orifices 133 a are portrayed as thicker, as will beseen later in FIG. 17A. The installation also includes three A3 arms116, each including three mounting saddles 134 b near top portion 132 b,and also includes three reinforced orifices 133 b. Portions 114 b of theweb 131 b nearest the orifices 133 b are portrayed as thicker, as willbe seen later in FIG. 19A. The installation also includes an A2 arm 118with two mounting saddles 134 c near top portion 132 c, and alsoincludes two reinforced orifices 133 c. Portions 114 c of the web 131 cnearest the orifices 133 c are portrayed as thicker, as will be seenlater in FIG. 21A. As can be seen in FIG. 15 , the openings 133 a, 133b, 133 c are parallel, or partly parallel to the saddles 134 a, 134 b,134 c atop each of the rack arms 114, 116, 118. The openings in oneembodiment are about one-quarter inch (6 mm) wide, although other widthsmay be used. The openings may about one-half inch to one-inch (13 mm to25 mm) long, although other opening lengths may be used.

FIG. 15A depicts a close-up view of the arm 118 of FIG. 15 . Web 131 chas a nominal thickness in most areas. Note, however, how portions 114 cof web 131 c are thicker near the orifices 133 c. Of course, the ribs137 are also considerably thicker than web 131 c, the ribs typicallyextending the full width of the top portion 132 c and the ribs narrowingso that the ribs also extend the full width of the bottom portion 138 c.See FIG. 12 , depicting each of the rack arms 114, 116, 118 having ribsthat extend from top to bottom or from the proximal side to the bottom.The portions of the ribs nearest the top have a width equal to the widthof the top, and the portions of the ribs nearest the bottom or side havea width equal to a width of the bottom or the side, which are typicallymore narrow than the width of the top or top flange. Other ribs withless than a full extension may also be used. The full-extension ribs areeasier to manufacture and work well in the field.

It may be important to smooth all transitions between portions of thecross arms, such as cross arms 114, 116, 118. Any changes in part shapeor thickness should be generously radiused, so that there are no sharpcorners or abrupt transitions. Corner radii of 0.0625 inches to 0.125inches may be used. In other examples, corner radii, internal andexternal, of 3/32 inch, 0.09375 inches or another dimension may be used.As seen in FIGS. 13 and 13A for cross arm 130, there are manydimensional transitions between the central web 131 and the upperportion 132, between web 131 and ribs 137, and between central web 131and orifice 133. The same holds true for the other cross arms 114, 116118, as shown in FIG. 15 . There should be generously radiusedtransitions between each central web 131 a, 131 b, 131 c, and lowerflange 138 a, 138 b, 138 c, between web 131 a, 131 b, 131 c and the ribsin each of the rack arms. There should also be gentle transitionsbetween web 131 a, 131 b, 131 c and the orifices 133 a, 133 b, 133 c,and so forth.

The situation may be better understood with reference to FIGS. 16, 16Aand 16B. FIG. 16 depicts a standard prior art 4-saddle A4 rack arm 160with an upper flat portion 161 a interrupted by four saddle mounts 161b, and also includes lower flange 162, web 163, ribs 164, vertical sideproximal portion 165 and mounting orifices 166. Web 163 has a uniformnominal thickness. Proximal portion 165 and mounting holes 166constitute an interface portion of the rack arm for interfacing with astanchion for mounting the rack arm. It is possible that one or moreribs 164 do not extend all the way from lower flange 162 to upperportions 161 a, 161 b, or to the vertical side 165. Rack arm 160 mayinclude one or more apertures or orifices 167 that are suitable for usewith cable ties (not shown) to secure power or communications cables orconduits to the rack arm. FIG. 16A is a cross-sectional view of FIG. 16. The orifice 167 is depicted in FIG. 16A as an opening in web 163. Intesting this A4 rack arm of the prior art, it was found that the armcould withstand a maximum load of 1400 pounds placed in the center 168of outermost saddle mount 161 b. Finite element analysis (FEA) showedthat this resulted in a point of maximum stress of 46 ksi at an inboardpoint 169 on the second of the four tie-down orifices. The load, stressand deflection are shown graphically in FIG. 16B. As noted previously,corners 163 a should be generously radiused.

The present disclosure may be better understood with reference to FIGS.17, 17A and 17B. FIG. 17 depicts an A4 rack arm 170 in which theapertures or orifices have been reinforced by increasing the thicknessof the web surrounding the apertures. Rack arm 170 includes an upperflat portion 171 a interrupted by four saddle mounts 171 b, and alsoincludes lower flange 172, web 173, ribs 174, vertical side proximalportion 175 and mounting orifices 176. The left side of the rack arm inthis instance constitutes the interface portion of the rack arm,including side portion 175 and mounting orifices 176. It is possiblethat one or more ribs 174 do not extend all the way from lower flange172 to upper portions 171 a, 171 b, or to the vertical side 175. Rackarm 170 may include one or more apertures or orifices 177 that aresuitable for use with cable ties (not shown).

FIG. 17A is a cross-sectional view of FIG. 17 . The orifice 177 isdepicted in FIG. 17A as an opening in web 173. Note that web 173 has anominal thickness in most areas of the rack arm, but in areas nearorifices 177, the web is much thicker. Note that areas of web 173 ofnominal thickness have a rectangular cross section. Thus, FIGS. 17 and17A depict an improved A4 rack arm with areas surrounding the orificesthicker than other, nominal areas of web 173. As seen in FIGS. 17 and17A, at least one rib 174 may extend from upper flange 171 a to lowerflange 172. At least one rib 174 may intersect with the portion of theweb 177 a having a thickness greater than the nominal thickness of theweb. In FIG. 17 , the right-most orifice intersects with both the upperflange and the lower flange, while two of the diagonal ribs intersectwith portions of the web having a thickness greater than the nominalthickness of the web. In some embodiments, the thickness of the web area177 a near orifice 177 may be twice as thick as web 173 itself. In otherembodiments, the reinforced areas may be only slighter thicker, withperhaps a 10-25 percent increase in thickness. Other embodiments mayhave a thickness increase from 25 percent to 75 percent. Yet otherembodiments may have a transition area that is more than twice as thickas the web, i.e., an increase of more than 100%. In one example, web 173has a nominal thickness of 9/32 inches (0.281 inches, 7 mm), and areasof the web near orifices 177 are twice as thick, 9/16 inches (0.5625inches, 14 mm) Other web thicknesses may be used and other stressattenuator thicknesses may be used. Note that in this embodiment, thereinforced area 177 a extends from the bottom of the upper surface,e.g., from the bottom of the saddle mounts 171 b to the orifice 177.This may also be an advantage in tooling, in that there is at least oneless transition for the manufacturer of the part. As noted above, alltransitions in thickness should be gentle, with no sharp corners andgenerously-radiused transitions.

As noted, FIGS. 17-17A depict an improved rack arm according to thepresent disclosure. In testing, it was found that the arm couldwithstand a maximum load of 2200 pounds 178 placed in the center of theoutermost-saddle mount. Finite element analysis (FEA) showed that thisresulted in a point of maximum stress of 46 ksi 179 at an inboard pointon the second of four tie-down orifices. The load, stress and deflectionare shown graphically in FIG. 17B. Note by comparison, the prior art armof FIGS. 16 and 16A could withstand only 1400 pounds of load. Furthertesting showed that if the force applied was 1400 pounds, the point ofmaximum stress remained the same, but with a maximum stress of 29 ksi,an improvement (stress reduction) of 1 minus 29 ksi divided by 46 ksi,that is, 0.37, which multiplied by 100 percent, equals 37%. Accordingly,an increased interface thickness around the openings or orifices may beconsidered to be a stress attenuator. Alternatively, for a given maximumstress, 46 ksi, the stress attenuator feature may be considered toincrease the load-bearing capacity of the arm, in this case from 1400lbs. to 2200 lbs. This is an increase of 57 percent, a significantincrease.

Next for consideration is an A3 rack arm, with reference to FIGS. 18,18A and 18B. FIG. 18 depicts a standard prior art 3-saddle A3 rack arm180 with an upper flat portion 181 a interrupted by three saddle mounts181 b. This A3 arm also includes lower flange 182, web 183, ribs 184,vertical side proximal portion 185 and mounting orifices 186. Proximalportion 185 and mounting holes 186 constitute an interface portion ofthe rack arm for interfacing with a stanchion for mounting the rack arm.Web 183 has a uniform, nominal thickness. It is possible that one ormore ribs 184 do not extend all the way from lower flange 182 to upperportions 181 a, 181 b, or to the side 185. Rack arm 180 may include oneor more apertures or orifices 187 that are suitable for use with cableties (not shown). FIG. 18A is a cross-sectional view of FIG. 18 . Theorifice 187 is depicted in FIG. 18A as an opening in web 183. As noted,FIG. 18 depicts an A3 rack arm of the prior art. In testing, it wasfound that the arm could withstand a maximum load of 1600 pounds placedin the center 188 of the outermost saddle mount. Finite element analysis(FEA) showed that this resulted in a point of maximum stress of 39 ksiat an outer point 189 on the middle of the three tie-down orifices. Theload, stress and deflection are shown graphically in FIG. 18B. Externaland internal corners 183 a should be rounded.

An improved version of an A3 rack arm is disclosed in FIGS. 19, 19A and19B. In improved A3 rack arm 190, the apertures or orifices have beenreinforced by increasing the thickness of the web surrounding theapertures. Rack arm 190 includes an upper flat portion 191 a interruptedby three saddle mounts 191 b, and also includes a lower flange 192, web193, ribs 194, vertical side proximal portion 195 and mounting orifices196. Proximal portion 195 and mounting orifices 196 constitute aninterface for mounting the rack arm to a stanchion. It is possible thatone or more ribs 194 do not extend all the way from lower flange 192 toupper portions 191 a, 191 b, or to the side 195. Rack arm 190 mayinclude one or more apertures or orifices 197 that are suitable for usewith cable ties (not shown). FIG. 19A is a cross-sectional view of FIG.19 . The orifice 197 is depicted in FIG. 19A as an opening in web 193.FIG. 19 depicts an improved A3 rack arm. Areas of the web surroundingthe orifices are noticeably thicker than other areas of web 193.

In some embodiments, the thickness of the web area 197 a near orifice197 may be twice as thick as web 193 itself. In other embodiments, thereinforced areas may be only slighter thicker, with perhaps a 10-25percent increase in thickness. Other embodiments may have a thicknessincrease from 25 percent to 75 percent. Yet other embodiments may have atransition area that is more than twice as thick as the web, i.e., anincrease of more than 100%. In one example, web 193 has a nominalthickness of 9/32 inches (0.281 inches, 7 mm), and areas of the web nearorifices 217 are twice as thick, 9/16 inches (0.5625 inches, 14 mm), anincrease of 100%. In another examples, the web has a nominal thicknessof 5/16 inches (0.3125 inches, 8 mm), and the stress attenuator has athickness of 19/32 inches (0.594 inches, 15 mm), a 90% increase. Inother embodiments, thicknesses of less than 90% or more than 100% mayalso be used. Note that in this embodiment, the reinforced area 197 aextends from the bottom of the upper surface, e.g., from the bottom ofthe saddle mounts 191 b to the orifice 197. This may also be anadvantage in tooling, in that there is at least one less transition forthe manufacturer of the A3 arm. As noted above, all transitions inthickness should be gentle, with no sharp corners andgenerously-radiused transitions. Corners 197 b, internal and external,should be rounded.

In testing the improved A3 rack arm, it was found that the arm couldwithstand a maximum load of 2500 pounds placed in the center 198 of theoutermost-saddle mount. Finite element analysis (FEA) showed that thisresulted in a point of maximum stress of 39 ksi at an outer point 199 onthe middle of the three tie-down orifices. The load, stress anddeflection are shown graphically in FIG. 19B. Note by comparison, theprior art arm of FIGS. 18 and 18A could withstand only 1600 pounds offorce. Further testing showed that with 1600 pounds of load applied, thepoint of maximum stress remained the same, but with a maximum stress of25 ksi, an improvement (stress reduction) of 1 minus 25 ksi divided by39 ksi, that is, 0.36, which, multiplied by 100%, equals 36%.Accordingly, an increased interface thickness may be considered to be astress attenuator. Alternatively, for a given maximum stress, 39 ksi,the stress attenuator feature may be considered to increase theload-bearing capacity of the arm, in this case from 1600 lbs. to 2500lbs. This is an increase of 56 percent, a significant increase.

The next disclosure concerns an A2 rack arm, with reference to FIGS. 2020A and 20B. FIG. 20 depicts a standard prior art 2-saddle A2 rack arm200 with an upper flat portion 201 a interrupted by two saddle mounts201 b. The arm also includes lower flange 202, web 203, ribs 204,vertical side proximal portion 205 and mounting orifices 206. Web 203has a uniform, nominal thickness. The vertical side proximal portion andmounting orifices 206 provide an interface for mounting the rack arm toa stanchion. It is possible that one or more ribs 204 do not extend allthe way from lower flange 202 to upper portions 201 a, 201 b, or to thevertical side 205. Rack arm 200 may include two apertures or orifices207 that are suitable for use with cable ties (not shown) to securepower or communications cables to the arm. FIG. 20A is a cross-sectionalview of FIG. 20 . The orifice 207 is depicted in FIG. 20A as an openingin web 203. Corners 203 a should be generously radiused. As noted, FIG.20 depicts an A2 rack arm of the prior art. In testing, it was foundthat the arm could withstand a maximum load of 1800 pounds placed in thecenter 208 of the outermost saddle mount. Finite element analysis (FEA)showed that this resulted in a point of maximum stress of 30 ksi at anoutboard point 209 on the inner tie-down orifice. The load, stress anddeflection are shown graphically in FIG. 20B.

An improved version of an A2 rack arm is disclosed in FIGS. 21, 21A and21B. In improved A2 rack arm 210, the apertures or orifices have beenreinforced by increasing the thickness of the web surrounding theapertures. Rack arm 210 includes an upper flat portion 211 a interruptedby two saddle mounts 211 b, and also includes lower flange 212, web 213,ribs 214, vertical side proximal portion 215 and mounting orifices 216.The vertical side portion 215 and mounting orifices 216 form aninterface for mounting arm 210 to a stanchion. It is possible that oneor more ribs 214 do not extend all the way from lower flange 212 toupper portions 211 a, 211 b, or to the vertical side 215. Rack arm 210may include two apertures or orifices 217 that are suitable for use withcable ties (not shown) as described previously.

FIG. 21A is a cross-sectional view of FIG. 21 . The orifice 217 isdepicted in FIG. 21A as an opening in web 213. Thus, FIGS. 21 and 21Adepict an improved A2 rack arm with areas of the web 213 surrounding theorifices thicker than other areas of the web. In some embodiments, thethickness of the web area 213 a near orifice 217 may be twice as thickas web 213 itself. In other embodiments, the reinforced areas may beonly slighter thicker, with perhaps a 10-25 percent increase inthickness. Other embodiments may have a thickness increase from 25percent to 75 percent. Yet other embodiments may have a transition areathat is more than twice as thick as the web, i.e., an increase of morethan 100%. In one example, web 213 has a nominal thickness of 9/32 inch,0.28125 inches or 7 mm, and areas of the web 213 a near orifices 217 are9/16 inch thick, 0.28125 inches thicker (7 mm), a total thickness of0.5625 inches (about 14 mm) an increase of 100%. Other increases inthickness, both less than 100% or greater than 100% may be used instead.

Note that in this embodiment, the reinforced area 217 a extends from thebottom of the upper surface, e.g., from the bottom of the saddle mounts211 b to the orifice 217. This may also be an advantage in tooling, inthat there is at least one less transition for the manufacturer of theA2 arm. As noted above, all transitions in thickness should be gentle,with no sharp corners and generously-radiused transitions. Note thatwhen arm 210 is molded, it is important that internal corners arerounded or radiused, as well as external corners, such as those formedabout orifice area 213 a. Thus, where the wider web portion 213 a meetsweb 213 having nominal thickness, the internal corner 213 b should beradiused. In a similar manner, external corners 213 a should also berounded or radiused.

In testing the improved A2 rack arm, it was found that the improved A2arm could withstand a maximum load of 2700 pounds placed in the center218 of the outer saddle mount. Finite element analysis (FEA) showed thatthis resulted in a point of maximum stress of 30 ksi at an outer point219 of the inner tie-down orifice. The load, stress and deflection areshown graphically in FIG. 21B. Note by comparison, the prior art arm ofFIGS. 20 and 20A could withstand only 1800 pounds of loading. Furthertesting showed that with an 1800 pound load, the point of maximum stressremained the same, but with a maximum stress of 20 ksi, an improvement(stress reduction) of 1 minus 20 ksi divided by 30 ksi, 0.33, which,multiplied by 100%, equals 33%. Accordingly, an increased interfacethickness may be considered a stress attenuator. Alternatively, for agiven maximum stress, 30 ksi, the stress attenuator feature may beconsidered to increase the load-bearing capacity of the arm, in thiscase from 1800 pounds to 2700 pounds. This is an increase of 50 percent,a significant increase.

Tables 1 and 2 below tabulate the testing conducted on prior art armsand arms manufactured with a stress attenuator, showing the benefit oflocal reinforcement around openings or orifices in the cable rack arms.

TABLE 1 STRESS REDUCTION WITH STRESS ATTENUATOR (S.A.) FEA max. stressFEA max stress Stress reduction Arm Load (lbs.) w/o s.a. with s.a. withs.a. RA-20 LP + s.a. 1300 24 17 29 RA-14 LP + s.a. 1300 37 24 35 A4 +s.a. 1400 46 29 37 A3 + s.a. 1600 39 25 36 A2 + s.a. 1800 30 20 33

TABLE 2 INCREASED LOAD-BEARING CAPACITY WITH STRESS ATTENUATOR (S.A.)Max. load w/o s.a., Max. load with s.a., Bearing load Arm FEA stress ksilbs. lbs. increase with s.a. RA-20 LP + s.a. 24 1300 1800 38 RA-14 LP +s.a. 37 1300 2000 54 A4 + s.a. 46 1400 2200 57 A3 + s.a. 39 1600 2500 56A2 + s.a. 30 1800 2700 50

We now continue with the flat arm embodiments. Embodiments of thisdisclosure are depicted in FIG. 22 , which depicts an underground cableinstallation 220 with two stanchions 228 secured to concrete wall 4 viabolts 6 (only one bolt visible in FIG. 22 ). The stanchions may beexisting metallic stanchions, such as single flange stanchions, doubleflange steel stanchions, TEE flange stanchions, E-flange stanchions, andthe like. Alternatively, the stanchions may be non-metallic, such asnon-metallic C-channel stanchion 228. In this instance, each stanchion228 is used to mount a first lower cable flat arm rack 222, threeadditional flat arms 223, 224, 225, and final top cable rack arm 226. Ascan be better seen in FIG. 23 , flat arm cable rack arms do not havemounting saddles for power or communication cables, but they do havevertical orifices so cables or conduits can be secured to the rack arms.Cable rack arm 222 in one embodiment is about 26 inches (660 mm) wideand would be able to accommodate four each 6-inches (150 mm) wideconduits or 3 each 8-inches (200 mm) wide conduits, such as a power orcommunications cables 18 along with a conduit or insulation 19. Manyother combinations of cable sizes and quantities may be mounted instead.Other embodiments may include a 21-inch (530 mm) wide flat arm 223, a16-inch (400 mm) wide flat arm 224, an 11-inch (280 mm) wide flat arm225, and 6-inch (150 mm) wide flat arm 226. The cables or conduits maybe secured to the arms with cable ties 17, discussed above. The portionsof the rack arms nearest the stanchion are referred to as the proximalportions, while the portions of the rack arms farthest removed from thestanchion are the distal portions. The proximal portions of the rackarms form an interface for mounting to the stanchion.

A less-encumbered perspective view of the installation is depicted inFIGS. 23-23A, showing pultruded plastic stanchion 228 with the cablerack arms described above with reference to FIG. 22 . The stanchion issecured to the concrete wall via one or more bolts 6 using holes orapertures (see FIGS. 25 and 25A) that are molded into the web of thestanchion. Stanchion 228 has a C-shaped cross section, as will also beexplained later with respect to FIGS. 25 and 25A. The rack arms aresecured to the stanchion with pins or bolts 221, which may be plasticbolts, and cotter pins 221 a. The cotter pins are inserted into orificesmolded into the flanges of the stanchions.

A rear perspective view of flat rack arm 223 is presented in FIG. 24 .FIGS. 24A, 24B and 24C present additional views. Flat arm 223 has aproximal end 223 a and a distal end 223 b. It has a relatively flat top223 m, an up-turned tip 223 n, and a series of through-orifices 223 o.Arm 223 also has side walls 223 p on either side of the arm, as can bemore readily appreciated from FIG. 24A. In one embodiment, the sidewalls may be about 0.25″ (about 6 mm) thick. In other embodiments, thewalls may have a variable thickness to allow for a draft angle for atool when the part is molded. For example, in one embodiment, the sidewalls may be about 0.25″ (6 mm) on the bottom and about 0.30″ (8 mm)thick where the side wall meets the top surface. In another embodiment,the side walls may be about 0.281″ (7 mm) thick at the bottom and about0.3125″ (8 mm) where the side wall meets the top. The top may be 0.25″(6 mm) thick, or it may be about 0.375″ (9-10 mm) thick. In anotherembodiment, the top may vary in thickness, e.g., thinner at the distalor far end and thicker near the proximal end. For example, in oneembodiment, the top may be about 0.375″ (9-10 mm) thick at the proximalend and yet have a thickness of about 0.25″ (6 mm) at the distal or farend. Other embodiments may have other thicknesses. Proximal end 223 aalso includes a substantial vertical notch or hollow 223 e, allowing arm223 to be mounted to a variety of other types of stanchions, asdiscussed above with reference to FIGS. 22 and 23 .

Proximal end 223 a and the top 223 m may be manufactured to form aslightly-obtuse angle C, an obtuse angle being an angle greater than90°. The obtuse angle of the flat top with the flat portions 223 h, 223j on the rear or proximal end 223 a prevents downward rotation of arm223 past the point where the material of the rear surface meets theinner surface of the channel 228. The obtuse angle C in one embodimentis about 91.5 degrees and may range from about 90.5 degrees to about 95degrees in practice, although other angles may be used, such as a rightangle. Having angle C at 91.5° results in the flat arm top 213 m havingan upward tilt of 1.5°. Other angles may be used so that the flat armhas an upward tilt of from about 1.5° to about 5°. One example is anupward tilt of about 3°. This upward tilt compensates for thedeformation of the arm when it is under load by very heavy power andcommunication cables. In other embodiments, it may be desirable for therack arm top surface to be at a nominal angle different from horizontal(90°).

Thus, rack arm 223 may be biased to some extent for upward tilting ofthe rack arm on its distal end, near angle D. The bottom surfaces of theside walls 223 p form an acute angle D to the flat portion of top 223 m.The angle is less than 90°, and desirably less than 60°. The imaginaryapex of the angle formed by the top and the upward-tilting side wallbottom surface will be to the right of arm 223. In practice, angle D mayrange from about 10 degrees to about 50 degrees, and desirably fromabout 15 degrees to about 47 degrees. Angle D may be from about 20° toabout 30°. Other embodiments may include cable rack arms designed for anorientation of some other angle from horizontal.

Details of the proximal end 223 a of arm 223 are shown in FIG. 24C.Proximal end 223 a includes a vertical notch or hollow 223 e for easiermounting to a variety of stanchions, and horizontal mounting orifices229 a, 229 b. Proximal end 223 a also includes left and right halves 223c, 223 d with flat portions 223 f, 223 g, respectively. In FIG. 24C,roughly-rhomboid sections 223 h and 223 j may be molded flat to fitsnugly against C-channel, TEE bar, L-angle and E-channel stanchions onwhich the cable arm is mounted. These are the flat sections discussedabove that may be oriented from about 90.5 to 95 degrees to the plane ofthe top surface of the cable arm. Side reliefs 223 k, 223 l allow use ofthe cable rack arms in existing single flange installations or doubleflange stanchions having substantial weld formations that wouldotherwise interfere with their installation, or also with other flanges,e.g., TEE flanges, etc. In the view depicted in FIG. 24C, only the rightside wall 223 p can be seen. Both side walls are visible in FIG. 24A.The cable rack arm 223 top 223 m may be wider nearer proximal end 223 athan its distal end 223 b.

Flat arm 223 also includes what has been described above as stressattenuators. As shown in FIG. 24B, the material around each orifice 223o has been thickened to act as a stress reliever or stress attenuator.Recognizing that each penetration will act to increase stress,thickening the area around the penetrations will help to relieve thestress and thus act as a stress attenuator. Thus, the area 223 r aroundeach orifice 223 o has been thickened to act as a stress attenuator. Thetransition 223 s between the bottom surface of arm top 223 m and thestress attenuator 223 r should not be a sharp corner but should begenerously radiused, as described above for other stress attenuatorembodiments. Note that for the flat arms, the stress attenuator is allon the under-side of the arm, not on the top surface. The top surface ofthe flat arms should be kept flat for the convenience of mounting cablesand conduits atop the flat arm.

The stanchions that may be used for mounting the flat arms are disclosedin FIGS. 25, 25A and 25B. The FIG. 25 is a front perspective view ofstanchion 228, FIG. 25A is a rear perspective view of the stanchion.FIG. 25B is a close-up view of mounting orifice 228 d, having an ovalshape, for mounting the stanchion to a wall or other mounting surface.The flat rack arms used to support power or communications cable orconduits are mounted to channel stanchion 228 via mounting pins 221,secured with cotter pins 221 a (see FIGS. 23, 23A). The proximal orinterface portion of the flat rack arms include mounting holes ororifices for mounting pins 221 so the pins can secure the rack arms tostanchion 228. Stanchion 228 has a C-shaped cross section formed by web228 a and flanges 228 b on either side of web 228 a. The stanchionflanges may also have openings or orifices 228 c for mounting cable rackarms. The web 228 a may include orifices or openings 228 d for mountingto a mounting surface, such as a concrete wall, via bolts as discussedabove. Mounting orifice 228 d in web 228 a may be oval shaped or mayhave another desired shape.

A side view of the installation is presented in FIGS. 26, 26A and 26B.The installation includes one or more of stanchion 228 mounted toconcrete wall with bolts (not seen in FIG. 26 ). Rack arms 222, 223,224, 225 and 226 mount to the stanchion with molded pins 221 and aresecured with cotter pins 221 a. The top surface of each rack arm mayhold one or more cables or conduits 18 and insulation 19. Also visiblein FIG. 26 is the right side wall 222 p, 223 p, 224 p, 225 p, 226 p ofeach arm. Detail side view FIG. 26A depicts shorter flat arm 225 withtip 225 n and right side wall 225 p, the cables or conduits andassociated insulation secured with cable ties 17 and integral fastener17 a. Front perspective view FIG. 26B depicts a flat arm 225 with tip225 n using cable tie 17 to secure communication cables or conduit 18and insulation 19 to the arm, using orifice 225 o. Other cables conduitsmay also be mounted, e.g., fiber optic cables, etc.

In making and testing improved flat arms, three configurations wereused, as depicted in FIGS. 27, 28 and 29 and cross-sectional views 27A,28A, 29A and 29B. FIG. 27 depicts a flat arm, with no stress attenuatorsused for the top of the arm, and no ribs supporting the side walls. Flatarm 270 includes a top 271, side walls 272 (only left sidewall shown),back 273 and mounting orifices 274 (only one shown). The flat arm alsoincludes proximal portion 270 a, distal portion 270 b, a plurality oforifices 275 that penetrate through top 271 and up-turned arm tip 277.In testing, a load 278 is applied on top of the arm, the maximum load inone embodiment may be 1400 lb. The point of the maximum stress 279 thatresults from this load is found near the center of the arm on the top ofthe arm. FIG. 27A depicts a cross-sectional view taken from FIG. 27 ,showing top 271 and both sidewalls 272, along with orifice 275. In sideview FIG. 27B, which depicts the FEA resulting stresses, the 1400 lb.load is depicted near the tip of the arm, resulting in a maximum stressin the central portion of the top of the arm, the maximum stress beingabout 24 ksi. Note also the deflection in the arm after the load isapplied. In FIG. 27C, the failure mode is seen to be Euler buckling inthe side arms. In this embodiment, the buckling safety factor is foundto be 2.2. Cables sometimes move horizontally side-to-side due tothermal expansion, power surges or other moving mechanical forces,putting a horizontal load on the support arms. A safety factor above 1.0keeps the arm supporting the maximum vertical load. If the safety factorwere exactly 1.0, there could be no allowable horizontal movement, andthe arm would fail with only slight horizontal movement. This arm has asafety factor (s.f.) of 2.2, that is, the allowable movement is 2.2×maximum load buckling safety.

One improvement in the flat arms is to add stress attenuators to thearm. That is, the thickness of the area under each orifice is increased.FIG. 28 depicts improved flat arm 280, which includes a proximal end 280a, a distal end 280 b, top 281 and side walls 282 (only the leftsidewall shown). Flat arm 280 also includes a back 283, mountingorifices 284 (only one shown), orifices 285 taken through the top, andupturned tip 287. The area around each orifice 285 on the underside ofthe top is reinforced with a stress attenuator 286, that is, a thicknessincrease. In testing, a load 288 is applied on the top of the arm,simulating a load of cables or conduits atop the arm. In one embodiment,the maximum load may be 1400 lb., resulting in a stress of about 21 ksi.The point of maximum stress 289 resulting from this load is again foundnear the center of the arm, on the top surface of the arm, as shown.FIG. 28A depicts a cross-sectional view taken from FIG. 28 , showing top281 and both sidewalls 282, orifice 285 and stress attenuator 286. Notethat the thickness increase due to the stress attenuator is entirely onthe underside of top 281, so that the top surface of arm 281 remainsflat. In side view FIG. 28B, which depicts the FEA resulting stresses,the 1400 lb. load is depicted near the tip of the arm, resulting in amaximum stress of about 21 ksi in the central portion of the top of thearm. In FIG. 28C, the failure mode is seen to be Euler buckling in theside arms. This arm has a buckling safety factor of 2.2.

In one embodiment, the thickness of the top in the area near eachorifice may be doubled. In other embodiments, the reinforced areas maybe only slighter thicker, with perhaps a 10-25 percent increase inthickness. Other embodiments may have a thickness increase from 25percent to 75 percent. Yet other embodiments may have a transition areathat is more than twice as thick as the top, i.e., an increase of morethan 100%. In one example, top 281 has a nominal thickness of about0.375 inches (about 10 mm) near the proximal end and a nominal thicknessof about 0.25 inches (about 6 mm) near the distal end, i.e., near thetip 277. In another example, top 281 has a nominal thickness of 0.25inches (about 6 mm), and areas of the web 281 near orifices 285 are 0.5inches (about 12-13 mm) thick, 0.25 inches (about 6 mm) thicker, anincrease of 100%. In other embodiments, the thickness increase may besmaller, from 10-25 percent of the top surface thickness. In yet otherembodiments, the thickness increase can be more than 100 percent, e.g.,an increase from about 0.25 inches (6 mm) to 0.375″ (9-10 mm) or more,e.g., 0.3 inches (7-8 mm) to 0.40 inches (10 mm). Other increases inthickness, both less than 100% or greater than 100% may be used instead.In some embodiments the increased thickness of the stress attenuator maybe about 3/16 inch (0.1875 inches or about 5 mm) plus or minus 1/16 inch(0.0625 inches or about 1.5 mm). In the flat arms, the thicknessincrease generally is found on the underside of the arm, that is, thetop itself stays flat and the increased thickness is found on the bottomor underside—see FIGS. 28A, 29A.

Another improvement in the arm is depicted in FIG. 29 , namely, one ormore ribs that connect the sidewalls, in addition to the stressattenuator discussed above. Arm 290 includes three supporting ribs 292a, 292 b, 292 c, in addition to a series of stress attenuators 296 onthe underside of top 291. Arm 290 includes proximal portion 290 a,distal portion 290 b, top 291, sidewalls 292 (only left sidewall show inFIG. 29 ), back 293, mounting holes 294 (only one shown) and tip 297. Asnoted, arm 290 includes three ribs connecting the sidewalls 292 alongwith the stress attenuators. FIG. 29A is a cross section of FIG. 29taken at a stress attenuator 296, showing the increase in thickness ofthe top 291, on its underside only, and also depicting sidewalls 292,orifice 295 and stress attenuator 296. FIG. 29B is a cross section ofFIG. 29 taken at rib 292 a. Thus, the cross-sectional view includes top291, sidewalls 292, and rib 292 a connecting the sidewalls. It ispreferable to mold the arms with integral ribs as a one-piece moldedarm. It is also possible to mold the arms and then add the ribs, e.g.,by adhering them between the side walls with an adhesive, or by usingfasteners to attach the ribs.

In testing, a load 298 is applied to the top of arm 290 near outer tip297. As shown in the FEA diagram of FIG. 29C, a load of 1400 lbs.results in a maximum stress of 21 ksi. The point 299 of maximum stressis found near the center of the arm, as shown, on the top surface of thearm. In FIG. 29D, the failure mode is seen to be Euler buckling in theside arms. This arm has a buckling safety factor of 2.8

The ribs in this embodiment varied in thickness, from about 0.2656inches (7 mm) just under the bottom surface of the arm to 0.1875 inches(5 mm) thick at the farther end of the ribs. In other embodiments, theribs may be from about 0.3125″ (8 mm) thick just under the arm to about0.125″ (3 mm) thick at the other end. In other embodiments, the ribs maybe about 0.25″ (6 mm) thick, and the thickness of the rib may vary,typically thicker just under a top surface where reinforcement isneeded. The thickness of the rib may then taper off as the rib nears anopposite end (bottom portion) of the side walls. Other thicknesses ofribs may be used.

Because of the configuration of the flat arm rack arms, it is morepractical to place the ribs between the orifices on the top of the rackarm. Thus, as shown in FIG. 29 , ribs 292 a, 292 b, 292 c are placedbetween the stress attenuators 296 so as not to interfere with anydrainage that may be needed from the top of the arm, and also so as notto interfere with the use of wire ties to secure cables or conduits tothe top of the flat rack arm. The ribs also do not interfere withplacement of the stress attenuators on the underside of the top surface.The flat arms disclosed herein help to restrain and support heavy loads.The stress attenuators described herein also help to increase thecarrying capacity of the arms. The ribs and the stress attenuator helpto improve the ability of the flat arm rack arms to support heavy loads,such as the power and communications cables that rest upon the arms. Theribs additionally strengthen and stiffen the arms and, especially withrespect to an increase in buckling resistance, by increasing the sectionmodulus of the rack arms.

Table 3, presented here, describes the results of the design and testingof our flat arms cable rack arms. As discussed above, these cable rackarms have stress attenuators and may also have reinforcing rib(s)between the outer skins of the rack arms.

TABLE 3 STRESS REDUCTION AND INCREASED CAPACITY WITH STRESS ATTENUATOR(S.A.) Arm Load (lbs) FEA stress, ksi Stress reduction Load capacity21-inch flat arm 1400 24 0 1400 lbs With stress attenuator 1400 21 13%1600 lbs (+14%) With stress attenuator 1400 21 13% 1600 lbs (+14%) andside ribs

TABLE 4 INCREASED SAFETY FACTOR AND INCREASED BUCKLING STABILITY ArmLoad (lbs) Buckling safety factor Safety factor increase 21-inch flatarm 1400 2.2  0% With stress attenuator 1400 2.2  0% With stressattenuator 1400 2.8 27% and side ribs

The shapes described in this disclosure are intended to beapproximations. As such, they may not be perfect geometrical shapes,such as those described as having a shape of a “circle,” a “square,” an“oval” or “ovate” shape, other geometric shape, and so forth. When theseor other geometric or descriptive terms are used they are approximationsof the desired shape rather than adhering to strictly geometricalperfection. There will always be some variation from perfection in theshape of these described and claimed objects. It should be understoodthat the described or claimed objects, or the tools described herein foruse with such objects, have features that are approximations or“generally in the shape of a ______,” with the appropriate geometricterm inserted in the blank. For example, a surface described as parallelto another surface is understood to be generally parallel rather thanperfectly parallel. That is, the two surfaces may have a similarcurvature rather than a perfectly symmetrical curvature. Another term ofart used is “nominal thickness,” in which portions of the new, improvedcable rack arm have a nominal thickness greater than the bulk ormajority of the web of the arm, the area of greater thicknesssurrounding the aperture or orifice used for retaining a tie orrestraint to tie down one or more cables mounted on the rack arm. Thenominal thickness of the web is the general as-molded width or thicknessof the web, while the web has an intentionally-molded portion of greaterthickness, such as at least 25 or 50 percent thicker, in order to takeadvantage of the reduced stress or greater load-carrying capacity of therack arm, as described herein.

In a similar fashion, an object described as “E-shaped,” “U-shaped” or“C-shaped,” and so forth, is also an approximation and is understood tobe “generally E-shaped”, rather than a perfect shape of the letter E,“generally U-shaped,” rather than a perfect shape of the letter “U,” or“generally C-shaped,” rather than a perfect shape of a capital C, as thewriter intends and the reader interprets a particular term or passage.

All references, including publications, patent applications and patentscited herein are hereby incorporated by reference to the same extent asif each reference were individually and specifically indicated to beincorporated by reference and were set forth in its entirety herein.

The use of the terms “a,” “an,” and “the” and similar referents in thecontext of describing the disclosure (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the disclosureand does not pose a limitation on the scope of the disclosure unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe disclosure.

Preferred embodiments are described herein, including the best modeknown to the inventors for carrying out the disclosure. Variations ofthose preferred embodiments may become apparent to those of ordinaryskill in the art upon reading the foregoing description. Skilledartisans will use such variations as appropriate, and the inventorsintend for the disclosure to be practiced otherwise than as specificallydescribed herein. Accordingly, this disclosure includes allmodifications and equivalents of the subject matter recited in theclaims appended hereto as permitted by applicable law. Moreover, anycombination of the above-described elements in all possible variationsthereof is encompassed by the disclosure unless otherwise indicatedherein or otherwise clearly contradicted by context.

What is claimed is:
 1. A non-metallic cable rack arm, comprising: anupper portion formed between a proximal end and a distal end of thecable rack arm; a lower portion opposite the upper portion; and a webhaving a nominal thickness connecting the upper portion to the lowerportion, the web comprising at least one orifice for securing a loadatop the non-metallic cable rack arm, wherein at least a portion of theweb adjacent the at least one orifice comprises a thickness greater thanthe nominal thickness of the web and wherein the at least one portion ofthe web adjacent the at least one orifice has a radiused interface witha portion of the web having the nominal thickness, and wherein theportion of the web comprising the thickness greater than the nominalthickness of the web intersects at least one rib connecting the upperportion to the lower portion.
 2. The non-metallic cable rack arm ofclaim 1, wherein the thickness greater than the nominal thickness of theweb acts as a stress attenuator.
 3. The non-metallic cable rack arm ofclaim 2, wherein the thickness greater than the nominal thickness isdistributed equally on both sides of the web.
 4. The non-metallic cablerack arm of claim 2, wherein the thickness greater than the nominalthickness surrounds the at least one orifice on both sides of the web.5. The non-metallic cable rack arm of claim 1, further comprisingflanges on the upper portion and the lower portion and wherein the webcomprises a plurality of ribs connecting the upper portion with thelower portion.
 6. The non-metallic cable rack arm of claim 1, furthercomprising saddle mounts on the upper portion, at least one of thesaddle mounts parallel with the at least one orifice.
 7. Thenon-metallic cable rack arm of claim 1, wherein portions of the webhaving the nominal thickness have a rectangular cross section.
 8. Thenon-metallic cable rack arm of claim 1, further comprising an interfacenear the proximal end, the interface comprising a flat surface and atleast one of an angled mounting bracket and mounting holes contiguouswith a slot.
 9. The non-metallic cable rack arm of claim 1, wherein thethickness greater than the nominal thickness of the web is at least 1.25times the nominal material thickness of the web.
 10. A system comprisingthe non-metallic cable rack arm of claim 1, the system furthercomprising a stanchion for mounting the cable rack arm.
 11. The systemof claim 10, wherein the non-metallic cable rack arm is adapted forhingedly mounting to the stanchion.
 12. A non-metallic cable rack arm,comprising: an upper flanged portion formed between a proximal end and adistal end of the cable rack arm; a lower flanged portion opposite theupper portion; a web having a nominal thickness connecting the upperflanged portion to the lower flanged portion, the web comprising atleast one orifice for securing a load to the non-metallic cable rackarm, at least a portion of the web adjacent the at least one orificefurther comprising a thickness greater than the nominal thickness of theweb, wherein the at least one portion of the web adjacent the at leastone orifice has a radiused interface with a portion of the web havingthe nominal thickness; and an interface near the proximal end forsecuring the cable rack arm to a mounting stanchion, and wherein theportion of the web comprising the thickness greater than the nominalthickness of the web intersects at least one rib connecting the upperportion to the lower portion.
 13. The cable rack arm of claim 12,wherein the portion of the web adjacent the at least one orificecomprises a thickness at least 1.5 times the nominal thickness of theweb.
 14. The cable rack arm of claim 12, wherein the at least oneorifice has a flat portion that is parallel with the upper flangedportion.
 15. The cable rack arm of claim 12, wherein the at least oneorifice has a curved portion that is parallel with a mounting saddle ofthe upper portion.
 16. The cable rack arm of claim 12, wherein theinterface comprises horizontal orifices and a vertical slot contiguouswith the horizontal orifices.
 17. The cable rack arm of claim 16,wherein the vertical slot further comprises side reliefs adjoining theproximal end of the arm.
 18. The cable rack arm of claim 12, wherein theinterface comprises a flat surface and at least one angled bracket. 19.The cable rack arm of claim 12, wherein the upper flanged portioncomprises at least one mounting saddle.
 20. A cable rack arm,comprising: an upper portion formed between a proximal end and a distalend of the cable rack arm, the upper portion adapted for holding atleast one cable; a flanged lower portion opposite the upper portion, theflanged lower portion formed at an acute angle to the upper portion; aweb having a nominal thickness connecting the upper portion to the lowerportion, the web having at least one orifice for tying down the at leastone cable; and an interface near the proximal end, the interfacesuitable for mounting the cable rack arm on a flanged stanchion, whereinat least a portion of the web adjacent the at least one orifice furthercomprises a thickness greater than the nominal thickness of the web andwherein the at least one portion of the web adjacent the at least oneorifice has a radiused interface with a portion of the web having thenominal thickness, and wherein the portion of the web comprising thethickness greater than the nominal thickness of the web intersects atleast one rib connecting the upper portion to the lower portion.
 21. Thecable rack arm of claim 20, wherein the interface comprises horizontalorifices and a vertical slot contiguous with the horizontal orifices,the vertical slot further also comprising side reliefs adjoining theproximal end of the cable rack arm.
 22. The cable rack arm of claim 20,wherein the increased thickness of the web adjacent the at least oneorifice is effective to reduce a stress on the cable rack arm at least25 percent for a given load.
 23. The cable rack arm of claim 20, whereinthe increased thickness of the web adjacent the at least one orifice iseffective to increase a load-bearing capacity of the cable rack arm aminimum of 25 percent.
 24. The cable rack of claim 20, wherein the cablerack arm is molded as a single piece of non-metallic material.
 25. Asystem comprising the cable rack arm of claim 20, the system furthercomprising a non-metallic stanchion for mounting the cable rack arm. 26.The system of claim 25, wherein the non-metallic stanchion is made bypultruding.
 27. The cable rack arm of claim 20, wherein the web furthercomprises a plurality of ribs extending from the upper portion to thelower flanged portion.
 28. The cable rack of claim 20, wherein theinterface comprises heel stops.
 29. The cable rack arm of claim 20,wherein the upper portion is wider than the lower flanged portion nearthe distal end.
 30. The cable rack arm of claim 20, wherein the upperportion comprises at least one saddle.